Solid-state image sensor, production method of the same, and digital camera

ABSTRACT

The present invention provides a solid-state image sensor wherein the color shading is decreased, and/or a solid-state image sensor wherein the shading effect is outstanding. Moreover, the invention provides a digital camera having the solid-state image sensor. The solid-state image sensor of the present invention has color filters and/or apertures of a light blocking layer, and the center of the color filters and/or the center of the apertures of the light blocking layer is offset with respect to the center of a light-receiving part, in the direction to the center of a valid cell area. In each photodetecting cell of a preferred solid-state image sensor, micro-lenses are further placed on the light-receiving side of the solid-state image sensor, and preferably, the center of the micro-lens is similarly offset with respect to the center of the light-receiving part. Also, the digital camera is mounted with an above-described solid-state image sensor.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a solid-state image sensorhaving a function of decreasing a shading amount, a production methodfor the solid-state image sensor, and a digital camera using thesolid-state image sensor, and particularly to a solid-state image sensorwherein micro-lenses are placed on the photodetecting cells belonging tothe incident side, the production method of the solid-state imagesensor, and a digital camera using the solid-state image sensor.

[0003] 2. Description of the Related Art

[0004] Recently, video cameras and digital cameras have becomewide-spread in general. CCD-type or MOS-type solid-state image sensorsare used in these cameras. In such solid-state image sensors, aplurality of photodetecting cells having a light-receiving part (aphotoelectric converter) are arranged to form a matrix. The energy ofthe light incident to each photodetecting cell undergoes photoelectricconversion in the light-receiving part, generating a signal charge. Thegenerated signal charge is outputted to the external parts, via a CCDand a signal channel.

[0005] As shown in FIG. 32, a CCD-type solid-state image sensor 10 ofthe related art has a photodetecting cell 13 having a light-receivingpart 2, a vertical CCD 15 and a horizontal CCD 16 constituting thelight-receiving part 2 for transferring signal charges, and an outputamplifier 17.

[0006] Among the photodetecting cells placed in the light receiving area(the area to which the light is incident) of the solid-state imagesensor 10, there are valid cells wherein the energy of the light,incident to the light-receiving part 2, undergoes a photoelectricconversion into a signal charge for outputting said signal charge, andthere are photodetecting cells for outputting dark currents withoutphotoelectric conversion.

[0007] A photodetecting cell which outputs dark currents is known, forinstance as a black dummy. Such a photodetecting cell has an incidentside which is shielded from the light, and is generally placed in onerow and/or one column surrounding the valid cell area wherein aplurality of valid cells are arranged to form a matrix, or in a row atthe extremity of any side of the valid cell area where a plurality ofvalid cells are arranged to form a matrix.

[0008] In addition, the solid-state image sensor 10 is equipped with alight-blocking layer such that the light is only incident to thelight-receiving part 2 of the valid cells, and with signal drivingchannels for applying voltage to CCD electrodes, not shown in FIG. 32.

[0009] In addition, color filters are placed above each light-receivingpart, for taking color pictures with the solid-state image sensor 10.

[0010]FIG. 33 is a layout view showing an example of an array of colorfilters. The plurality of color filters together forms a layer. R, G andB represent red, green and blue filters, respectively. One of the R, Gor B filters is placed above the light-receiving part 2.

[0011] In addition, to improve the converging power, a micro-lens issometimes placed above each light-receiving part 2. FIG. 34 is across-sectional view showing the structure of a photodetecting cell ofthe solid-state image sensor 10 of the related art.

[0012] In the above-mentioned solid-state image sensor 10, thelight-receiving part 2 is formed on top of the semiconductor substrate 1(for example a silicon substrate), a light blocking layer 9 withapertures 8 is placed on the incident side of the light-receiving part2.

[0013] Above each light-receiving part 2, one of the R, G and B colorfilter 4 is placed in an on-chip fashion. In addition, a micro-lens 7for improving the converging power is placed immediately above thelight-receiving part 2, via a flattening layer 6.

[0014] In fact, in such a solid-state image sensor 10, a phenomenoncalled shading is known which gives rise to sensitivity fluctuations inthe valid cell area.

[0015] Shading originates from the fact that incident lights incident tothe peripheral part of the valid cell area, when compared to incidentlights incident to the central part of the valid cell area, haveincidences which are oblique. In other words, when the light isobliquely incident, it generates eclipses and a degradation of thephotoelectric conversion rate at the level of the light-receiving part2.

[0016] In this case, since the quantity of incident lights in thecentral part of the valid cell area is greater, for the same quantity ofincident lights, the output signal is greater for the photodetectingcells of the central part when compared to the photodetecting cells ofthe peripheral part. Therefore, a “sensitivity fluctuation” is generatedbetween the photodetecting cells of the central part and thephotodetecting cells of the peripheral part. Also, in this document, the“sensitivity fluctuation (or the difference in the output value)” iscalled the shading amount. The shading amount increases when the numberof photodetecting cells increases, and the size of the valid cell areaincreases.

[0017]FIG. 35 shows an example of results obtained when the shadingamount is measured for a solid-state image sensor.

[0018] The measurements of the shading amount shown in FIG. 35 have beenobtained by measuring the output of a valid cell area, whose size was25.1 mm in the horizontal direction and 16.9 mm in the verticaldirection. In the drawing, Δ is the G output voltage of the central part(sensitivity, equivalent to the actual aperture rate),  is thecalculated value for the latter, X is the actual measurement of the Goutput voltage for the peripheral part, and □ is the calculated value ofthe latter.

[0019] From this figure, it is clear that the shading amount between thecentral part and the peripheral part depends on the F number of thedigital camera, the result of which is displayed as the difference inthe G output voltage (sensitivity).

[0020] A so-called “micro-lens positional offsetting” method, whereinthe center of micro-lens belonging to the peripheral part is movedtowards the central part of the valid cell area, taking the center ofthe corresponding light-receiving part as the reference, and a methodwherein the aperture width of the light blocking layer is larger thecloser to the periphery it is, taking the center of the correspondinglight-receiving part as the reference, have been proposed as methods fordecreasing such shading amounts.

[0021] Of these, the “micro-lens positional offsetting” is publiclyknown, for instance, as disclosed in Japanese patent No. 2600250.

[0022] In the “micro-lens positional offsetting”, as shown in FIG. 36,the center of a micro-lens 27 installed above a light-receiving part(for example a photovoltaic such as a photodiode) 22, is matched withthe center of a light-receiving part 22 (double-broken lines in thedrawing) in case the light-receiving part belongs to the central part21A of the valid cell area 21, and offset by a specified distance d1towards the central part of the valid cell area 21, in case thelight-receiving part belongs to the peripheral part 21E of the validcell area.

[0023] The specified distance d1 is defined so it becomes greater at aconstant rate, the further from the center 21X of the solid-state imagesensor 20. In addition, optimal values are determined for the specifieddistance d1, taking into consideration the characteristics of the cameralenses and the solid-state image sensor 20 actually used. In addition,in the drawing, numeral 23 is an inter-level isolation layer, numeral 24is a color filter and numeral 26 is a flattening layer.

[0024] The “micro-lens positional offsetting” shading countermeasurementioned above has been recognized to be effective to some extent, butit is still not sufficient. The reasons are explained concretely in thefollowing.

[0025] First, the above-mentioned shading countermeasure has the problemof not taking into account the solid-state image sensors wherein colorfilters are placed on the incident side, thereby generating colorshading due to said color filters. Color shading designates the offsetof color balance between the central part and the peripheral part.

[0026] Second, when applying the “micro-lens positional offsetting”,which offsets the position of the lenses, to actually-made solid-stateimage sensors, it has not been possible to decrease the shading to thesame extent as the values calculated in simulations. In addition, theaperture area of the light blocking layer mounted in the solid-stateimage sensor has not been taken into consideration. In other words,although when the aperture area of the light blocking layer is wider,the light leak increases and leads to such a problem as cross-talk,which is one of the effects due to shading, and a malfunction of switchtransistors, these phenomena have not been taken into account in the“micro-lens positional offsetting”.

[0027] Third, when designing in shading countermeasures, thecharacteristics of the digital camera, wherein the correspondingsolid-state image sensor is applied, have not been taken into account.In other words, the F number of the camera lens equipped in digitalcameras, and/or the actual F number change the angle of incidence of thelight with respect to the light-receiving part, and this F numberdependency of the incident angle influences the shading amount.

[0028] In the related art, taking into account this F number dependencyof the shading amount, a correction to increase the brightness of theperipheral part by an image processing device installed in the cameraside, has been considered (a software shading correction). This shadingcorrection is performed as the step 1 of image processing (FIG. 37)executed by the computer of a digital camera carrying the solid-stateimage sensor 10. However, to execute the shading correction program, itis normally necessary to equip the digital camera side with a specialcontrol circuitry, which raises the costs. In addition, when the shadingamount is large, by executing this shading correction, the efficiency ofother processes requiring faithful color reproduction degrades andcauses the problem of the image itself becoming unnatural. In addition,when the shading value is large, depending on the performance of thecomputer loaded onto the camera, rapid image processing can bedifficult. The defect becomes a larger problem for CCD-type solid-stateimage sensors with an increased valid cell area.

[0029] In addition, the above-mentioned F number dependency of shadingbecomes particularly problematic, in the case of exchangeable lens-typedigital still cameras, when the camera lens unit is substituted (whenexchanging lenses).

[0030] Furthermore, the decrease in the shading amount by “micro-lenspositional offsetting” is limited in the width of the offset, since itis a method wherein correction is made by offsetting the position of themicro-lens with respect to the position of the light-receiving part(photovoltaics). This is particularly a problem for large-sizesolid-state image sensors (film-size CCD-type solid-state image sensors)wherein the degree of oblique incidence is extremely large, and wherenot enough offset width can be maintained.

SUMMARY OF THE INVENTION

[0031] The present invention has been conceived in view of the above,and its first object is to provide a solid-state image sensor which candecrease even color shading, and/or a solid-state image sensor withsuperior shading effects, and a digital camera using such solid-stateimage sensor.

[0032] The second object of the present invention is to provide asolid-state image sensor which decreases shading independent from theaperture reserved at the light blocking layer, and/or a solid-stateimage sensor with superior shading effects, and digital camera usingsuch solid-state image sensor.

[0033] In addition, the third object of the present invention is toprovide a solid-state image sensor wherein the shading amount of asolid-state image sensor can be decreased while lowering the F numberdependency, in a simple structure.

[0034] In addition, the fourth object of the present invention is toprovide a solid-state image sensor wherein the shading amount of thesolid-state image sensor can be decreased accurately in response to anactual environment of a digital camera taking pictures.

[0035] In order to achieve the above-mentioned objects, the solid-stateimage sensor of the present invention comprises a valid cell areawherein a plurality of light-receiving parts and a plurality of validcells having color filters placed in an on-chip fashion corresponding tothe light-receiving parts and outputting charge signals, are arranged toform a matrix, the color filters placed in the peripheral part of thevalid cell area are offset with respect to the light-receiving parts inthe direction to the center of the valid cell area, and the offsetamounts between the color filters and aforementioned light-receivingparts become gradually or continuously larger, the further it is fromthe center and the closer it is to the periphery of the valid cell area.The above configuration makes it possible to appropriately offset thecolor filters with respect to the position of the light-receiving parts,and color mixture is decreased even when oblique incident lightcomponents are present.

[0036] Preferably, in the solid-state image sensor, the valid cell areais divided into groups of a plurality of concentric blocks, with theoffset amount between the color filters and the light-receiving partsbeing the same within each block, and increasing from the central partto the peripheral part. The above configuration not only allows adecrease in color mixture, but also allows use of a relatively low-costreticle as a reticle for making color filters when producing solid-stateimage sensors, and also decreases production costs.

[0037] In addition, another solid-state image sensor of the inventioncomprises a valid cell area wherein a plurality of light-receiving partsand a plurality of valid cells having color filters placed in an on-chipfashion to correspond to the light-receiving parts and outputting chargesignals, are arranged to form a matrix, the color filters placed in theperipheral part of the valid cell area are offset with respect to thelight-receiving parts in the direction to the center of the valid cellarea, the light-receiving parts and the color filters are placed on arespective constant pitch, with the pitch for the light-receiving partsbeing greater than the pitch for the color filters. This configurationmakes it possible to make the difference of the offset amounts betweenthe color filters and the light-receiving parts continuous from thecentral part to the peripheral part of the valid cell area. Imagesobtained from such solid-state image sensors present more naturalphotographic subjects.

[0038] In addition, another solid-state image sensor of the presentinvention comprises a valid cell area, having a plurality of validcells, each comprising a light receiving part and a light blocking layerin which apertures are provided corresponding to the light-receivingpart, for outputting charge signals arranged to form a matrix, theapertures reserved at the peripheral part of the valid cell area areoffset with respect to the light-receiving parts in the direction of thecenter of the valid cell area, and the offset amounts between theapertures and aforementioned light-receiving parts become gradually orcontinuously larger, the further it is from the center and the closer itis to the periphery of the valid cell area. The above configurationmakes it possible to appropriately offset the apertures with respect tothe position of the light-receiving parts, and the shading amount can bedecreased without generating eclipses, even when oblique incident lightcomponents are present.

[0039] Preferably, the valid cells of the solid-state image sensor aredivided into groups of a plurality of concentric blocks, with the offsetamount between the apertures and the light-receiving parts being thesame within each block, and the offset amounts being larger as it getsfurther from the central part and closer to the peripheral part. Theabove configuration not only allows a decrease in the shading amount,but it also allows use of a relatively low-cost reticle for making theapertures of a light blocking layer, and decreasing the productioncosts.

[0040] In addition, yet another solid-state image sensor of the presentinvention is equipped with a valid cell area wherein a plurality oflight-receiving parts and a plurality of valid cells having a lightblocking layer in which apertures are reserved to correspond to thelight-receiving parts and outputting charge signals, are arranged toform a matrix, the apertures reserved at the peripheral part of thevalid cell area are offset with respect to the light-receiving parts inthe direction to the center, the light-receiving parts are placed andthe apertures are reserved with a respective constant pitch, with thepitch for the light-receiving parts being greater than the pitch for theapertures. This configuration allows to make the difference of theoffset amounts between the apertures of the light blocking layer and thelight-receiving parts continuous from the central part to the peripheralpart of the valid cell area, thus, the images obtained present morenatural photographic subjects.

[0041] In addition, when considering the application of each of theabove-mentioned solid-state image sensors of the present invention todigital cameras, the offset between the center of the light-receivingparts and the center of the micro-lenses equipping the incident side,the offset between the center of the light-receiving parts and thecenter of the color filter, and the offset between the center of thelight-receiving parts and the center of the apertures can be determinedbased on the total thickness of layers, the thickness of the layerbetween the light-receiving parts and the layer equipped with themicro-lenses, the thickness of the layer between the light-receivingparts and the color filters, the thickness of the layer between thelight-receiving parts and the apertures, the refractive index of thelayer placed underneath the micro-lenses and the eye-relief of theoptical system equipped in the digital camera.

[0042] In addition, yet another solid-state image sensor of the presentinvention has a valid cell area formed by a plurality of photodetectingcells made of a plurality of photovoltaics arrayed on the main side of asemiconductor substrate, in which, according to the position of thephotovoltaics inside the valid cell area, on the light receiving side ofthe corresponding photovoltaic, a penetration adjusting device is placedto adjust the optical penetrating amount of the corresponding incidentlight. This allows proper reduction in the shading amount which differsaccording to the position of the valid cell area.

[0043] Preferably, the penetration adjusting device of the solid-stateimage sensor is a layer made of organic materials, formed in the upperpart of the photovoltaics, which has different optical penetrationamount according to the position inside the valid cell area. Thisallows, by only changing the optical penetrating rate of the layer madeof organic material, composition for an optimal decrease of the shadingamount without modification of other structures.

[0044] In addition, preferably, in the solid-state image sensor,micro-lenses are configured in the layer made of organic material,formed on the light receiving side of the photovoltaics, and havedifferent optical penetrating rates depending on the position from theperipheral part to the central part of the valid cell area. This allows,by only changing the optical penetrating rate of the micro-lenses, inother words, without modification of other structures, composition foran optimal decrease of the shading amount.

[0045] In addition, preferably, in the solid-state image sensor,micro-lenses are placed on the light receiving side of thephotovoltaics, with the layer made of organic material serving as theflattening layer formed between the photovoltaics and the micro-lenses.This allows, by only changing the optical penetrating rate of theflattening layer, in other words, without modification of otherstructures, composition for an optimal decrease of the shading amount.

[0046] When producing such solid-state image sensor, a layer is formed,wherein the optical penetrating rate changes according to theirradiation amount due to ultra-violet rays, and the layer isselectively exposed to ultra-violet rays in an amount which changesaccording to the position of the valid cell areas. This allows, by onlyadjusting the amount of ultra-violet irradiation occurring during thegenerally performed “added exposure”, production of a solid-state imagesensor with an optimal decrease of the shading amount.

[0047] In addition, preferably, a layer is formed wherein the opticalpenetrating rate changes according to the temperature of heating, andthe layer is heat-treated, according to the position of the valid cellareas. This allows, by only adding a simple production process,production of a solid-state image sensor with an optimal decrease of theshading amount.

[0048] In addition, preferably, the penetration adjusting device isplaced on the light receiving side of the valid cell area, and functionsas an optical penetrating rate controlling device capable of controllingthe optical penetrating rate. Fine control (decrease) of the shadingamount is possible using the optical penetrating rate controllingdevice.

[0049] In addition, preferably, in the solid-state image sensor, theoptical penetrating rate controlling device controls the opticalpenetration rate based on the signals from the brightness sensor mountedin the surrounding of the valid cell area. This allows for a proper andoptimal decrease of the shading amount according to the actualenvironment of a digital camera taking pictures.

[0050] Solid-state image sensors configured as mentioned above aremounted into digital cameras. This allows for correction of the shadingaccording to the environment of a digital camera taking pictures.

BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The nature, principle, and utility of the invention will becomemore apparent from the following detailed description when read inconjunction with the accompanying drawings in which like parts aredesignated by identical reference numbers, in which:

[0052]FIG. 1 is a planar view of a CCD-type solid-state image sensor 100of the present invention.

[0053]FIG. 2 is a cross-sectional view of the solid-state image sensor100 in relation to a first embodiment of the present invention.

[0054]FIG. 3 shows the solid-state image sensor 100 in relation to avariation example of the first embodiment of the present invention, with(a) being a planar view and (b) being a cross-sectional view.

[0055]FIG. 4 is a table indicating the sizes and offset amounts for asolid-state image sensor 110, a variation example of the firstembodiment.

[0056]FIG. 5 is a cross-sectional view of a solid-state image sensor 120in relation to a second embodiment of the present invention.

[0057]FIG. 6 is a cross-sectional view of a solid-state image sensor 150in relation to a third embodiment of the present invention.

[0058]FIG. 7 is a measurement graph relating offset amount (Sm) betweena light-receiving part and a micro-lens, and the signal output from thephotodetecting cell, when the interval between the light-receiving partand the micro-lens is varied.

[0059]FIG. 8 is a Figure for explaining the parameters required tocalculate the “appropriate offset amount”, wherein (a) is across-sectional view showing the configuration of a photodetecting cellof the solid-state image sensor 150, (b) is a view showing thesubstantial part of a digital camera loaded with the previous element,and (c) is a magnified view of the surroundings of the micro-lens.

[0060]FIG. 9 is a cross-sectional view showing the light paths obtainedwhen simulating how the light converges at the level of each of thephotodetecting cells placed in the central part and in the peripheralpart of the valid cell area belonging to the solid-state image sensor150.

[0061]FIG. 10 is a graph showing the relationship between the F numberof the optical system of a digital camera loaded with a solid-stateimage sensor and the converging power.

[0062]FIG. 11 is a table showing each parameter of a digital camera inrelation to a fourth embodiment.

[0063]FIG. 12 is a cross-sectional view of a solid-state image sensor200 of a fifth embodiment of the present invention.

[0064]FIG. 13 is a view showing the arrangement of a color filter 204according to the Bayer array.

[0065]FIG. 14 is a planar view showing the layout of a block 210A, ablock 210B, etc., of the solid-state image sensor 200.

[0066]FIG. 15 is a cross-sectional view showing a production process ofthe solid-state image sensor 200 of a fifth embodiment.

[0067]FIG. 16 is a planar view showing the layout of a mask area 250A,mask area 250B, . . . , and mask area 250E, of a mask 250.

[0068]FIG. 17 is a planar view showing the patterns of micro-domains inthe mask, for differentiating the optical penetrating rate for ultraviolet rays of the mask area 250A, the mask area 250B, . . . , and themask area 250E.

[0069]FIG. 18 is a view showing the overall structure of a digitalsingle-lens reflex camera 300 loaded with the solid-state image sensor200.

[0070]FIG. 19 is a graph showing the difference between the G outputvoltage when the optical penetrating rate for ultra-violet rays is 0%and the G output voltage when the optical penetrating rate forultra-violet rays is 100%, as a function of the F number.

[0071]FIG. 20 is a planar view showing another layout of the block 210A,the block 210B, . . . of the solid-state image sensor 200.

[0072]FIG. 21 is a planar view showing yet another layout of the block210A, the block 210B, . . . of the solid-state image sensor 200.

[0073]FIG. 22 is a cross-sectional view showing a production process ofthe solid-state image sensor 200 of a sixth embodiment.

[0074]FIG. 23 is a view of the part of a production process of a seventhembodiment of the solid-state image sensor 200 showing how the opticalpenetrating rate is modified by heating a micro-lens 207.

[0075]FIG. 24 is a cross sectional-view of an eighth embodiment of asolid-state image sensor 400.

[0076]FIG. 25 is a view of the part of a production process of theeighth embodiment of the solid-state image sensor 400, showing how theoptical penetrating rate is modified by heating a flattening layer 403.

[0077]FIG. 26 is a graph showing the difference between the effectiveaperture ratio when the optical penetrating rate of the flattening layer403 is 100% and the effective aperture ratio when the opticalpenetrating rate of the flattening layer 403 is 70%, as a function ofthe F number, in the solid-state image sensor 400.

[0078]FIG. 27 is a view showing the cross-sectional form and the planarform of a ninth embodiment of a solid-state image sensor 500.

[0079]FIG. 28 is across-sectional view showing a magnification of a partof an optical penetrating rate controlling layer (EC layer) 600.

[0080]FIG. 29 is a view showing the positioning pattern of a lightsensor 561 in the periphery of a valid cell area 510 of the solid-stateimage sensor 500.

[0081]FIG. 30 is a view showing the cross-sectional form and the planarform of the solid-state image sensor 500 in relation to a variationexample of the ninth embodiment.

[0082]FIG. 31 is a view showing an optical penetrating rate controllinglayer (EC layer) 800 for use in a CCD of a tenth embodiment FIG. 32 is across-sectional view of a CCD-type

[0083] solid-state image sensor 10 of the previous art.

[0084]FIG. 33 is a layout view showing an example of arrangement of thecolor filters of the solid-state image sensor 10 of the previous art.

[0085]FIG. 34 is a cross-sectional view of the solid-state image sensor10 of the previous art.

[0086]FIG. 35 is a graph showing the effects due to shading correctionin the solid-state image sensor 10 of the previous art, as a function ofthe F number.

[0087]FIG. 36 is a cross-sectional view of a solid-state image sensor 20wherein the “micro-lens positional offsetting” method of the previousart has been applied.

[0088]FIG. 37 is a correction flow chart showing the image processingperformed on the digital camera side.

[0089]FIG. 38 shows the cross-sectional structure of the peripheral partof valid cell area of a solid-state image sensor 30 of the previous art,with (a) being a cross-sectional view for simplifying explanation and(b) being a cross-sectional view of a case where a more homogeneouscontrol of the thickness of the color filter layer has been performed.

[0090]FIG. 39 is a cross-sectional view of the peripheral part of validcells belonging to a solid-state image sensor 40 of the previous art.

[0091]FIG. 40 is a cross-sectional view of a magnified part of asolid-state image sensor 50 wherein the “micro-lens positionaloffsetting” method of the previous art has been applied.

DESCRIPTION OF THE PREFERRED EMBODIMENT First Embodiment

[0092] In the following, the first embodiment according to the inventionwill be explained referring to the drawings.

[0093] To begin with, the reasons which led the inventors to theinvention of the first embodiment will be explained.

[0094] The inventors determined that the cause of the above-mentionedcolor shading (first problem) was attributable to color mixing due tothe oblique incidence of the light. FIG. 38 is a cross-sectional view ofthe peripheral part of a valid cell area (the region where valid cellsare arranged to form a matrix) of a solid-state image sensor 30 whereinthe “micro-lens positional offsetting” has been applied.

[0095] In FIG. 38, (a) is a view for explaining and (b) is a view of acase where a more homogeneous control of the thickness of the colorfilter layer has been performed. In addition, here, the light blockinglayer is omitted.

[0096] A light-receiving part 32 is placed above a semiconductorsubstrate (silicon substrate, for example) 31 and a micro-lens 36 isplaced by offsetting the position with respect to the light-receivingpart 32, to decrease shading. The micro-lens 36 is formed above aflattening layer 35. A CCD electrode 37 is placed between thelight-receiving part 32 and the light-receiving part 32. A silicon-oxidelayer 39 is placed to isolate the CCD electrode 37 and protect thelight-receiving part 32.

[0097] A color filter 34 is formed above an inter-level isolation layer33 by the spin-coating method, for each color. When produced as above,the thickness of the filter layer differs depending on the colors, andsteps are generated. To give an example, in contrast to a thicker 2.5 μmthick color filter 34-1, a thinner color filter 34-2 would be about 1.2μm thick.

[0098] When a step is generated between the color filters 34-1 and 34-2which are different from each other, the light passes also through thecolor filter of the adjacent photodetecting cell, following the pathindicated by numeral 38 a.

[0099] This is the cause of color mixing. Color mixing is generated bythe oblique incidence of the light, as above. However, the obliqueincident light component decreases towards the central part of the validcell area.

[0100] Therefore, between the central part and the peripheral part ofthe valid cell area, the degree of color mixing is different, andaccordingly, the color balance also differs between the central part andthe peripheral part of the valid cell area.

[0101] In addition, as in (b) of FIG. 38, for example, even if an idealhomogeneity of the thickness of the layer could be controlled, with thespin-coating method, the periphery of the filter formed afterwards israised. Therefore, it is still a cause of color mixing.

[0102] The solid-state image sensor 100 of the first embodiment isconfigured such that the center of the color filters placed at theperiphery of the valid cell area is offset with respect to the center ofthe light-receiving parts, in the direction of the center of the validcell area, as described in detail below. This allows decrease of colorshading due to the above causes.

[0103] A concrete explanation is given below.

[0104]FIG. 1 is a planar view of a CCD-type solid-state image sensor 100of the previous art, and FIG. 2 is a cross-sectional-view showing theconfiguration of the photodetecting cell of the solid-state image sensor100 in relation to a first embodiment of the present invention. Inaddition, in the solid-state image sensor 100 of FIG. 1, the pitch of alight-receiving part 102 is greater than the pitch of a color filter104, offsetting the center of the color filter 104 with respect to thecenter of the light-receiving part 102. Furthermore, in FIG. 1 numeral132 is a vertical CCD, numeral 133 is a horizontal CCD and numeral 134is an output amplifier.

[0105] The light-receiving part 102 of the solid-state image sensor 100is placed with a constant pitch at the top of a semiconductor substrate101, as shown in FIG. 2. On top of these, via an inter-level isolationlayer 103, a color filter 104 is placed in an on-chip fashion. The colorfilter 104 is also placed with a constant pitch, however, it is smallerthan the pitch of the light-receiving part 102.

[0106] In this case, in the central part of the valid cell area whereina plurality of valid cells are arranged to form a matrix, the center ofthe light-receiving part 102 of a photodetecting cell coincides with thecenter of the corresponding color filter 104. Then, at the level of eachphotodetecting cell, the offset amounts between the centers of thelight-receiving parts 102 and the centers of the color filters 104become gradually larger, the further it is from the central part, andthe closer it is to the peripheral part.

[0107] Such a configuration allows decrease of color shading due tooblique incident lights, in the solid-state image sensor 100. Inaddition, the difference between the offset amounts between the centerof the color filter 104 and the center of the light-receiving part 102is gradual, from the position closer to the central part, to theposition closer to the peripheral part of the valid cell area. Thisallows for images obtained from the solid-state image sensor 100 topresent more natural photographic subjects.

[0108] In addition, in this case, a micro-lens 107 is placed above aflattening layer 106. The pitch of the micro-lens 107, when compared tothe pitch of the color filter 104, is smaller. Such a configurationallows further decrease in the shading amount. In addition, theconverging power of each photodetecting cell in the solid-state imagesensor 100 is improved evenly.

[0109] In fact, FIG. 2 schematically shows the structure of thephotodetecting cells in the central part and the photodetecting cells inthe peripheral part of the valid cell area belonging to the solid-stateimage sensor 100. As shown in FIG. 2, in the peripheral part of thevalid cell area, the micro-lens 107, the color filter 104 and thelight-receiving part 102, drawn on top of the broken line, form one setcorresponding to a configuration of one photodetecting cell.

[0110] For example, in the solid-state image sensor 100 of the firstembodiment, the size of one side of the photodetecting cell is 10 μm,the size of the valid cell area is 24 mm×16 mm and the size of thelight-receiving part 102 is 8 μm×4 μm.

[0111] In addition, the offset amount for the color filter 104 in theedge part of the valid cell area is designed to be 3 μm in the directionof the long side and 1 μm in the direction of the short side.

[0112]FIG. 3 is a figure for explaining the solid-state image sensor 100in relation to a variation example of the first embodiment, wherein (a)is a planar view and (b) is a cross-sectional view.

[0113] In FIG. 3(a), an A block, a B block and a C block represent thevalid cell area, and a D block represents an optically opaque part, or aperipheral circuit part.

[0114] The valid cell area is divided into concentric groups, from thecentral part to the peripheral part. In the central A block, the centerof a light-receiving part 112 coincides with the center of a colorfilter 114 corresponding to the light-receiving part 112. On the otherhand, in the photodetecting cell of the other blocks, the center of thecolor filter 114 is offset with respect to the center of thelight-receiving part 112, in the direction of the center of the validcell area. In addition, the offset amount (SOCF) is constant within eachblock, and is greater in the peripheral part. For example, it is greaterin the B block than in the C block.

[0115] Such a configuration, as in the case of the solid-state imagesensor 100 shown in FIG. 1 and FIG. 2, allows the offset amounts betweenthe centers of the light-receiving parts 112 and the centers of thecolor filters 114 to become gradually larger, the further it is from thephotodetecting cells in the center and the closer it is to thephotodetecting cells in the periphery. This results in the decrease ofcolor shading due to oblique incident lights. In this case, a micro-lens117 is placed above a flattening layer 116. In addition, in FIG. 3(b),numeral 111 is a semiconductor substrate, numeral 113 is an inter-levelisolation layer.

[0116] In this case, the center of the micro-lens 117 in the B and Cblocks, as is the case for the color filter 114, is offset with respectto the center of the light-receiving part 112, in the direction of thecenter of the valid cell area. In addition, the offset amount (Sm) isconstant within each block. In addition, the offset amount (Sm) isgreater than SOCF, and the offset amount of the block closer to theperipheral part is greater. This allows not only a further decrease inthe shading amount, but also improvement in the converging power.

[0117] The appropriate value for a concrete “offset amount” is differentdepending on the size of the cell, the thickness of each layer, and soforth. The “appropriate offset amount” is described below.

[0118] An example of the sizes of the solid-state image sensor 100 ofthe current embodiment and offset amounts are shown in FIG. 4. Theoffset amount is different between the X direction and the Y direction,owing to a difference in the size of the valid cell area between the Xdirection and the Y direction.

[0119] In fact, semiconductor devices having the microscopic patternsthat the solid-state image sensor 100 has, are produced using aphotolithography apparatus called a stepper. The photolithographyapparatus transfers the pattern of a reticle onto the top of asemiconductor substrate.

[0120] The reticle is obtained by patterning a layer of metal such aschrome on the top of a silicone glass plate. The cost is higher forreticles having finer microscopic patterns formed in the metal layer. Ahigh-cost reticle is required to produce a solid-state image sensor.

[0121] As described above, in the solid-state image sensor,differentiating the pitch of the color filters or the pitch of themicro-lenses from the pitch of the light-receiving parts (as in the caseof the solid-state image sensor of FIG. 2 ) involves changing SOCF or Smby a minute amount (in the order of 0.01 μm) for each photodetectingcell.

[0122] If a characteristic of the solid-state image sensor (for example,color reproducibility) is important, the offset amount between the colorfilter and the light-receiving part can be made so that the differencein offset amounts according to different positions is continuous fromthe central part to the peripheral part of the valid cell area. In thiscase, however, an even higher cost reticle is required.

[0123] In contrast, if the offset amount is different for each block asin the case of the solid-state image sensor 110 shown in FIG. 3, acomparatively rough accuracy of the pattern on the reticle isacceptable. Therefore, a low-cost reticle can be used, which decreasesthe production cost.

[0124] In either case, it is possible to decrease the color shading,with the solid-state image sensor 100 or 110 of the embodiment. Eitherconfiguration may be selected according to the objective for the use ofthe solid-state image sensor or the degree of freedom in the design anddevelopment.

Second Embodiment

[0125] In the following, the second embodiment according to theinvention will be explained using FIG. 5.

[0126] The inventors determined the cause of the problem (the secondproblem, i.e. the eclipse) wherein the shading amount differs dependingon the shape of the aperture reserved at the light blocking layer.

[0127] This is explained below. FIG. 39 is a cross-sectional view of theperipheral part of the valid cell area belonging to a solid-state imagesensor 40 of the previous art. Also, the color filter is omitted.

[0128] The “micro-lens positional offsetting” is applied to thesolid-state image sensor 40, so that the center of a micro-lens 46 isplaced to be offset with respect to the center of a light-receiving part42 taken as the reference. In addition, in the drawing, numeral 41 is asemiconductor substrate.

[0129] As it is clear from the Figure, even if the center of themicro-lens 46 is offset with respect to the center of thelight-receiving part 42, if an aperture 49 of a light blocking layer 47is reserved immediately above the light-receiving part 42, an obliqueincident light 45 b is generated, blocked by the light blocking layer47. This is why, it was not possible to decrease the shading amount aseffectively as the simulations.

[0130] In a solid-state image sensor 120 of the second embodiment, thecenter of the aperture in the peripheral part of the valid cell area isoffset with respect to the center of the light-receiving part, in thedirection of the center of the valid cells. This configuration makes itpossible to decrease the shading amount due to the above-mentionedcause.

[0131] A concrete explanation is given below.

[0132]FIG. 5 is a cross-sectional view showing the structure of thesolid-state image sensor 120 in relation to the second embodiment of thepresent invention.

[0133] In the solid-state image sensor 120, by increasing the pitch of alight-receiving part 122 to be greater than the pitch of an aperture 129of a light blocking layer 126 (simply called aperture, hereafter), thecenter of the aperture 129 is offset with respect to the center of thelight-receiving part 122.

[0134] In other words, the light-receiving part 122 is placed with aconstant pitch on top of a semiconductor substrate 121. Above these, thelight blocking layer 126 containing the aperture 129 is placed via aninter-level isolation layer 128. The aperture 129 is also reserved witha given constant pitch which is smaller than the pitch of thelight-receiving part 122. In addition, in the drawing, numeral 127 is amicro-lens.

[0135] In this case, in a photodetecting cell belonging to the centerpart belonging of the valid cell area, the center of the light-receivingpart 122 coincides with the center of the corresponding aperture 129.This allows the offset amounts between the apertures 129 and thelight-receiving parts 122 to gradually become larger, the further it isfrom the photodetecting cells of the central part and the closer it isto the photodetecting cells of the peripheral part. This results in afurther decrease of the shading amount due to oblique incident lights.In addition, the offset amounts between the center parts of apertures129 and the centers of the light-receiving parts 122 are continuouslydifferent from the central part to the peripheral part of the valid cellarea, allowing for obtained images to present photographic subjects morenaturally.

[0136] In addition, in the embodiment, the micro-lens 127 is placed onabove the inter-level isolation layer 128. Also, the pitch of themicro-lens 127, when compared to the pitch of the aperture 129, issmaller. As a result of this, not only is the shading amount furtherdecreased, but the converging power is also improved. In addition, themicro-lens 127, the aperture 129 and the light-receiving part 122, drawnon top of a broken line in FIG. 5, form one set corresponding to theconfiguration of one photodetecting cell.

[0137] In addition, in the embodiment, by changing the pitch of thelight-receiving part 122 and the pitch of the aperture 129, the shadingamount is decreased. However, the above does not constitute alimitation, and it is also acceptable to divide the valid cell area intogroups, as shown in the variation example of the first embodiment,offset the aperture -129 with respect to the light-receiving part 122 inthe direction of the center of the valid cell area, and make the offsetamount (SOPN) constant for each block. In this case, it suffices to makethe offset amount between the center of the light-receiving part and thecenter of the aperture, within the block of the peripheral part, greaterthan the offset amount in the central part. If the offset amount isdefined block by block as above, when forming the aperture of the lightblocking layer, a low-cost reticle can be used, which decreases theproduction cost for the solid-state image sensor.

Third Embodiment

[0138] In the following, the third embodiment according to the inventionwill be explained.

[0139]FIG. 6 is a cross-sectional view showing the configuration of asolid-state image sensor 150 in relation to a third embodiment of thepresent invention.

[0140] In addition, the planar layout of the solid-state image sensor150 is almost identical to the layout shown in FIG. 3(a). In otherwords, the valid cell area is divided into an A block, a B block and a Cblock (a D block represents an optically opaque part, or a peripheralcircuit part).

[0141] In this case, each photodetecting cell of the solid-state imagesensor, forms a light-receiving part 152 on top of a semiconductorsubstrate (a silicone plate) 151, and an aperture 159 of a lightblocking layer 156, a color filter 154 and a micro-lens 157 are placed,corresponding to the light-receiving part 152.

[0142] In the central A block, the center of the light-receiving part152 coincides with each of the center of the aperture 159, the center ofthe color filter 154 and the center of the micro-lens 157, correspondingto the light-receiving part 152.

[0143] On the other hand, at the level of the photodetecting cells ofthe other blocks, each of the center of the aperture 159, the center ofthe color filter 154, and the center of the micro-lens 157 is offsetwith respect to the center of the light-receiving part 152, in thedirection of the central part of the valid cell area.

[0144] The offset amounts (sequentially, SOPN, SOCF and Sm) for eachphotodetecting cell, are constant for the photodetecting cells containedin the same block, and are greater for photodetecting cell of a blockclose to the peripheral part. In addition, each offset amount for aphotodetecting cell, which is constant for each block, is related bySOPN SOCF Sm.

[0145] The above makes it possible for the offset amounts to becomegradually larger with respect to the light-receiving parts 152 of eachof the centers of the apertures 159, the centers of the color filters154 and the centers of the micro-lenses 157, in photodetecting cells,the further they are from the central part and the closer they are tothe peripheral part. Therefore, the shading and the shading amounts dueto oblique incident lights are decreased.

[0146] Here, a method for determining the “appropriate offset amount”with respect to a light-receiving part, for the aperture, the colorfilter and the micro-lens, will be explained referring to FIG. 7 andFIG. 8.

[0147]FIG. 7 is a measurement graph relating the “offset amount (Sm)”between a light-receiving part and a micro-lens, and the signal outputfrom the photodetecting cell, when the interval between the center ofthe light-receiving part and the center of the micro-lens is varied.

[0148] The horizontal axis is the “offset amount” of the micro-lens withrespect to the corresponding light-receiving part, and the vertical axisis the output voltage. In addition, in this case, the position of theaperture of the light blocking layer coincides with position of thecolor filter, and the “offset amount” of the micro-lens as well as thethickness of the flattening layer placed immediately underneath themicro-lens are varied. In other words, the distance between thelight-receiving part and the micro-lens is varied.

[0149] The thickness of the flattening layer is larger in the order of161, 162 and 163.

[0150] As is clear from the figure, an appropriate value (or range) todecrease the shading exists for the “offset amount” of a micro-lens, andit is revealed that the “appropriate offset amount” is largercorresponding to the distance between the micro-lens and thelight-receiving part being larger. FIG. 7 is the data on the offsetamount of the micro-lens.

[0151] However, if an appropriate value exists for the “offset amount”of a micro-lens, similarly, an “appropriate offset amount” should alsoexist for the aperture of a light blocking layer, or a color filter.

[0152] Therefore, based on the above-mentioned results, a number ofassumptions were made, leading to each “appropriate offset amount”.

[0153]FIG. 8 is a drawing for explaining the parameters required tocalculate the “appropriate offset amount”, wherein (a) is across-sectional view of the solid-state image sensor 150 of theinvention, (b) is a view showing the substantial part of a digitalcamera 160 loaded with the solid-state image sensor 150, and (c) is amagnified view of the surroundings of the micro-lens.

[0154] In FIG. 8, SOPN, SOCF and Sm are the “offset amounts” withrespect to the light-receiving part 152 for each of the center of theaperture 159, the center of the color filter 154 and the center of themicro-lens 157, respectively.

[0155] In addition, d3, d2 and d1 are the distances from the upper sideof the light-receiving part 152 to each of the upper side of theaperture 159, the upper side of the color filter 154, and the upper sideof the micro-lens 157, respectively.

[0156] In addition, as shown in FIG. 8(b), the digital camera 160,wherein the above-mentioned solid-state image sensor 150 is applied, hasan optical system 166, wherein a lens 167 and an iris 168 are placed. Inaddition, an optical system is shown in the drawing, having a two lensset of numeral 167-1 and numeral 167-2, but this does not constitute alimitation.

[0157] The light becomes incident to the solid-state image sensor 150,via the optical system 166.

[0158] Incident lights 169 have an almost perpendicular incidence in thecentral part of the valid cell area. On the other hand, in theperipheral part, incident lights 20 have an incidence other than a rightangle.

[0159] In this case, P, indicated in FIG. 8(b), is the distance betweenthe center of the valid cell area and the photodetecting cell for whichthe “appropriate offset amount” is calculated (generally called “heightof the image”), and 1 is the distance between the light receiving sideof the solid-state image sensor 150 and the iris 168 (generally called“eye-relief”).

[0160] The “appropriate offset amount” is sought with a number ofassumptions.

[0161] First, the “appropriate offset amount” is calculated taking therays incident to the center of each micro-lens (169 a, 170 a; tosimplify, will be called θ0 rays, hereafter), as the reference.

[0162] The light passing through the optical system 166 of the digitalcamera 160, actually has a certain spread centered around the incidentlight which passed through the center of the micro-lens at the level ofthe height of the image P, which is clear from FIG. 8(b). The lighthaving the aforementioned spread, becomes incident to the micro-lens ofthe solid-state image sensor, and exits to the light-receiving part.Therefore, by simulating each condition for taking a picture, forexample, the converging condition by micro-lenses, of a light fluxwherein the spread depends on the F number of the camera lens system, anaccurate calculation of an “optimal offset amount” is possible,according to the characteristics of actually mounted micro-lenses andcolor filters, and actually reserved apertures of light blocking layers.

[0163] Here θ0 rays are used as the reference. This makes it possible toconsider the camera lens and easily calculate the “optimal offsetamount” according to the characteristics of the micro-lens, color filteror aperture of a light blocking layer.

[0164] Second, each type of layer between the micro-lens and thelight-receiving part is assumed to have the same refractive index as therefractive index n of the layer immediately below the micro-lens. Then,the incident angle θ0 and the exit angle θ of the micro-lens aredetermined by the angle of the first refraction after the θ0 rays havearrived on the solid-state image sensor, as shown in FIG. 8(c).

[0165] In reality, in the solid-state image sensor, between themicro-lens and the light receiving part, a plurality of layers areformed such as the flattening layer, the color filter, the insulationlayer, the oxide layer. Therefore, strictly, since the refraction indexof each layer is different, the incident light is refracted in a complexmanner at the level of each layer. However, the difference in theindices being generally small, they are assumed to be constant(refraction index n), as described above. Following this assumption, therelationship between the incident angle θ0, the exit angle θ and therefraction index n, is expressed in the following equation, according toSnell's law:

sinθ=sinθ0/n  (1)

[0166] Third, although the incident lights output from the camera lenssystem are to first become incident to the micro-lenses, whether thereare micro-lenses or not, the θ0 rays are assumed to arrive on thelight-receiving part the via the same route. Therefore, the “appropriateoffset amount” calculated here is applicable to solid-state image sensorwithout micro-lenses.

[0167] In addition, measurement of the exit angle θ from the micro-lensis difficult in reality. Therefore, the incident angle θ0 at themicro-lens is defined by the following equation, using the height of theimage P, the eye-relief 1, the equation have being an approximation,obtained by taking into consideration geometrical considerations.

sinθ0=P/(P ²+1²)½  (2)

[0168] From equations (1) and (2), the exit angle is approximated by sinθ=P/[n×(p²+1²)^(½)] and the exit angle is defined here by the previousequation.

[0169] With the above-described approximation, the optimal values of Sm,SOCF and SOPN, i.e., the offset amounts with respect to thelight-receiving part for micro-lens, color filter and aperture, arecalculated with the following equations, as a function of the distancefrom the light-receiving part and the exit angle θ.

Sm=d1×tan θ  (3)

SOCF=d2×tan θ  (4)

SOPN=d3×tan θ  (5)

[0170] It is mostly preferred to use the above-mentioned equations inorder to calculate all of the “appropriate offset amounts” Sm, SOCF andSOPN, of the photodetecting cell of the valid cell area belonging to thesolid-state image sensor. However, even if not all of the Sm, SOCF andSOPN, are set to the values of the above equations, in other words, evenif one of the offset amounts Sm, SOCF and SOPN, is set to a valuecalculated using the above equation, there will be an effect on thedecrease in the shading amount.

[0171] Also, these “appropriate offset amounts” are theoretical valuesobtained by approximation, based on the above-mentioned equation.Because of errors in the accuracy of the semiconductor manufacturingtechnique, actually produced solid-state image sensors are not alwaysproduced exactly by offsetting micro-lenses, color filters and aperturesonly by the “appropriate offset amounts” obtained from the equations(3), (4) and (5). Therefore, “appropriate offset amounts” having theoptimal values of the above equations provided with a certain width, arepreferred. According to the experiments, it is possible to provide the“appropriate offset amounts” with a width of ±30%. Therefore, the“appropriate offset amounts” are calculated using the equations (6), (7)and (8), with the condition of satisfying the relation SOCF<SOPN<Sm.

0.7×d1×tanθ≦Sm≦1.3×d1×tan θ  (6)

0.7×d2×tanθ≦SOCF≦1.3×d2×tan θ  (7)

0.7×d3×tanθ≦SOPN≦1.3×d3×tan θ  (8)

[0172] Even if not all of the Sm, SOCF and SOPN, are not set to valuesin the ranges of the above equations, in other words, even if only oneof the offset amounts Sm, SOCF and SOPN, is set to a value in the rangesof the above equation, there will be an effect on the decrease in theshading amount.

[0173] In addition, if the “offset amounts” are to be changed for eachblock as in the case of the solid-state image sensor 110 shown in FIG.3, it suffices for the mean value of the off set amounts of each blockto fall within the ranges of the optimal values obtained with the aboveequations. This also makes it possible to achieve a decrease of theshading.

[0174] Here, it is clear that, focussing on equation (3) and equation(4), the optimal ratio between Sm and SOCF is given by the ratio betweend1 and d2, and focussing on equation (3) and equation (4), the optimalratio between Sm and SOPN is given by the ratio between d1 and d3. Theequations for calculating the optimal ratio are shown in (9) and (10).

Sm/SOCF=d1/d2  (9)

Sm/SOPN=d1/d3  (10)

[0175] In addition, if a width of +30% is to be provided, theappropriate ranges of ratio expressed by the above equations (9) and(10) are calculated with the equations (11) and (12) below, providedwith the width of ±30%.

0.7×(d1/d2)≦Sm/SOCF≦1.3×(d1/d2)  (11)

0.7×(d1/d3)≦Sm/SOPN≦1.3×(d1/d3)  (12)

[0176] Also in this case, even if the actually manufactured solid-stateimage sensor does not satisfy the conditions of both equations (11) and(12), if the ratio of at least one of the above equations is satisfied,there will be an effect on the decrease in the shading amount.

[0177] In addition, if the offset amounts are to be changed for eachblock as in the case of the solid-state image sensor 110 shown in FIG.3, it suffices for the mean value of the offset amounts of each block tofall within the ranges of the optimal values obtained with the aboveequations.

[0178]FIG. 9 is a cross-sectional view obtained by simulation, showinghow the light converges in a photodetecting cell of the central part,and how the light converges in a photodetecting cell of the peripheralpart, of the valid cell area belonging to a solid-state image sensor.

[0179] The upper part is the light path of the incident light when the Fnumber of the lens of the optical system placed on the digital camera is1.4, and the lower part is the light path of the incident light when theF number of the lens of the optical system placed on the digital camerais 11. In the drawing, (a) and (e) are photodetecting cells wherein themicro-lens and the aperture have been offset by the “appropriate offsetamounts” for photodetecting cells of the peripheral part, given by theabove-mentioned equations (6) and (8). In addition, (b) and (f) in thedrawing are photodetecting cells in which only the micro-lens has beensimilarly offset by the “appropriate offset amount”, (c) and (g) in thedrawing are comparative examples wherein neither have been offset, and(d) and (h) in the drawing are photodetecting cells of the center.

[0180] In the above simulation, the size of the photodetecting cell was10 μm×10 μm, the thickness of the micro-lenses was 2.5 μm the size ofthe aperture of the light blocking layer and the size of thelight-receiving part was 8 μm in the horizontal direction and 4 μm inthe vertical direction. In addition, the values for d1, d2 and d3 (Ref.FIG. 8(a)) were 7 μm, 5.5 μm and 2.5 μm, respectively

[0181] In addition, the offset amount for the micro-lenses of thephotodetecting cells of the peripheral part was 0.8 μm in the horizontaldirection and 0.6 μm in the vertical direction, in the direction of thecenter of the image-sensing side. In the photodetecting cells of theperipheral part, the center of the aperture of the light blocking layerwas offset by only 0.4 μm (offset amount) in the horizontal directionand 0.3 μm (offset amount) in the vertical direction, in the directionof the center of the valid cell area.

[0182] When the micro-lenses are offset with respect to thelight-receiving part, since the light converges in the center of thelight-receiving part, there is an effect on the decrease in the shadingamount (FIG. 9(b) and (f) ).

[0183] In addition, the existence of light components eclipsed by thelight blocking layer can be seen. When the light blocking layer isfurther offset, the incident lights are adequately incident to thelight-receiving part, and the shading amount is further decreased (FIG.9(a) and (e) ).

[0184] In other words, also from this simulation, it can be seen that,in the photodetecting cells of the peripheral part, by offsetting theposition of the micro-lens in the direction of the center of the validcell area, and by further offsetting the aperture of the light blockinglayer adequately with respect to the above offset micro-lens, obliquelyincident lights pass through the center of the aperture of the lightblocking layer and converge efficiently onto the light-receiving part.

[0185]FIG. 10 is a graph showing the relationship between the F numberof the lens used in the optical system of a digital camera, and theconverging power of a solid-state image sensor.

[0186] The relationship between the converging power and the F number isshown by a dotted line 171 for the photodetecting cells of the centralpart of a valid cell area (FIG. 9(d) and (h)), by a solid line 172 forthe photodetecting cells in the peripheral part wherein the micro-lensand the aperture have been offset to their respective appropriateposition ((a) and (e)), by a solid line 173 for the photodetecting cellof the peripheral part wherein only the micro-lens has been offset tothe appropriate position, and by a solid line 174 for the photodetectingcells of the peripheral part, wherein neither the micro-lens nor theaperture have been offset.

[0187] As can be seen also from this graph, the shading is improved evenwhen “positional offsetting” with respect to the light-receiving part isperformed only for the micro-lens, but the shading amount is furtherdecreased, by adequately performing a further “positional offsetting” ofthe aperture of the light blocking layer.

[0188] In addition, here, a configuration wherein the micro-lens and theaperture of the light blocking layer are offset with respect to thelight-receiving part have been explained as an example. However,equivalent simulation results have been obtained when the “positionaloffsetting” was performed not only for the micro-lenses and theapertures, but also for the color filters. In addition, with thisconfiguration, a further decrease in the color shading can be achieved.

Fourth Embodiment

[0189] The fourth embodiment according to the invention will beexplained in the following. FIG. 11 is a table showing each parameter ofa digital camera in relation to a fourth embodiment according to thepresent invention.

[0190] Not shown in the drawing, in the solid-state image sensor loadedon the embodiment, similarly to the solid-state image sensor 100 of thefirst embodiment, the pitch of the light-receiving part, and the pitchof each of the micro-lens, the color filter, and the aperture arevaried.

[0191] The pitch of the light-receiving part is set uniquely by thenumber of photodetecting cells which is dictated by the resolution powerrequired for the solid-state image sensor and the size of thesolid-state image sensor.

[0192] For example, if the size of the valid cell area is 24 mm in the Xdirection, and 1000 photodetecting cells are aligned in the X direction,the pitch of the light receiving part is 24 μm.

[0193] In the embodiment, in order to obtain the pitch for eachmicro-lens, color filter and aperture, the “offset amounts” for theoutermost part of the valid cell area are first obtained based on thepreviously explained equations (3), (4) and (5). Then, the pitch for theaperture is calculated from these “offset amounts”.

[0194] In fact, the “optimal offset amounts” obtained from equations(3), (4) and (5) do not necessarily change linearly from the centralpart to the peripheral part of the valid cell area. In such a case wherethe change is not linear, with the configuration of the embodiment, adeviation from the “appropriate offset amount” may occur forphotodetecting cells in an area other than the outermost part. In FIG.11, the “optimal offset amounts” calculated from equations (3), (4) and(5) are listed together with the actual offset amounts arising from theabove-mentioned pitch. In addition, the actual offset amount wasobtained from the equation below.

S=(S of the outermost photodetecting cell)×[p/(p of the outermostphotodetecting cell)]

[0195] From FIG. 11, it is clear that both “offset amounts” are almostthe same. However, in this case, the calculation is performed withpMax=15 mm.

[0196] The reason for the above-mentioned match is due to the fact that,as the height of the image decreases, the inclination θ of incidentlights inside the solid-state image sensor decreases, and theapproximation sin θ≈tan θ≈p/1 becomes applicable.

Fifth Embodiment

[0197] In the following, the fifth embodiment according to the inventionwill be explained referring to FIG. 12 to FIG. 21.

[0198] The inventors determined that, in the solid-state image sensor,even when the center of a micro-lens 57 of a peripheral part 51E of thevalid cell area is placed offset only by a specified distance d1 fromthe center of a light-receiving part 52 by applying the “micro-lenspositional offsetting”, a portion of the incident lights converged ontothe light-receiving part 52 by a micro-lens 57 of the peripheral part51E, can not become incident to the light-receiving part 52, dependingon their incidence angle, as shown in FIG. 40. This is because in thesolid-state image sensor, the specified distance d1, which is the“offset amount” for the micro-lens 57, is determined by taking apredetermined incidence angle (a value defined by the F number) as thereference.

[0199] Therefore, even in the case where the same camera lens is used,if the F number is changed by changing the aperture, a portion of theincident lights do not become incident to the light-receiving part 52 inthe peripheral part 51E, and the amount of converging light is decreasedwhen compared to the central part of the valid cell area, leading toshading occurring, as shown by the broken lines in FIG. 40. In addition,in the drawing, numeral 53 is an inter-level isolation layer, numeral 54is a color filter and numeral 56 is a flattening layer.

[0200] The solid-state image sensor 200 of the fifth embodimentdecreases the shading independently from the effective F number of thecamera lens.

[0201] A concrete explanation is given below.

[0202] A solid-state image sensor 200 of the fifth embodiment is acharge-coupled device-type (CCD-type) image sensor. In a valid cell area210, wherein valid cells are arranged to form a matrix, alight-receiving part 202 formed at the top of a semiconductor substrate201, a flattening layer 203, a color filter layer 204, a micro-lensstabilization layer 206, a micro-lens 207 are formed as shown in FIG.12. In this case, the light-receiving part 202 and the micro-lens 207are installed on each photodetecting cell of the valid cell area 210.

[0203] In this case, the main components of the flattening layer 203 arepropylene glycol monomethyl ether acetate (PGMEA) and propylene glycolmonoethyl ether acetate (PGEEA).

[0204] In addition, for the color filter layer 204, pigmentscorresponding to each color (red, green or blue) are dispersed inpropylene glycol monomethyl ether acetate (PGMEA) and propylene glycolmonoethyl ether acetate (PGEEA).

[0205] In addition, the main components of the micro-lens stabilizationlayer 206 are methyl 3-metoxy propionic acid (MMP) and acrylic resin.

[0206] In addition, the main components of the micro-lens 207 are PGEEA,ethyl lactate (EL) and phenolic resin.

[0207] In addition, as will be detailed later, the micro-lens 207 ismade to have different optical penetrating rates for the incident lights(optical penetrating rate) for each micro-lens in each area from acentral part 210A to the peripheral part 210E of the valid cell area 210(FIG. 14).

[0208] In this solid-state image sensor 200, a vertical transferelectrode, a horizontal transfer electrode and an amplifier for readingthe signal charge are installed, in the vicinity of the light-receivingpart 202 on the semiconductor substrate 201. In addition, in theperipheral part of the solid-state image sensor 200, other circuits suchas correlated double sampling circuits (omitted from the Figure) areinstalled on top of the same semiconductor substrate 201. In addition,the planar structure of the solid-state image sensor 200 is almostidentical to the solid-state image sensor 100 of the first embodimentand FIG. 12 corresponds to the section along X-X′ of FIG. 1.

[0209] In addition, for each light-receiving part 202, a predeterminedcolor is selected and stains the color filter 202 of the solid-stateimage sensor 200. For example, in the case of bayer array, green (G),blue (B) and red (R) pigments are implanted following the patternindicated in FIG. 13. In this case, the electric signal from thephotodetecting cell (light-receiving part 202) in which a green (G)filter is positioned is used as the signal indicating brightness (Goutput voltage).

[0210] The micro-lens 207 is configured to have different opticalpenetrating rates between the central part (block 210A) and theperipheral part (block 210E) of the valid cell area 210. The opticalpenetrating rate of the blocks 210B, 210C and 210D (FIG. 14) between thetwo areas change in a stepwise manner. In other words, the opticalpenetrating rate of each photodetecting cell is adjusted in a stepwisemanner according to its position inside the valid cell area 210.

[0211] By determining the optical penetrating rate for each of theseblocks 210A, 210B, . . . , according to, for instance, the F number ofthe camera lens actually used in a digital camera (refer to FIG. 18),the shading amount can be decreased for each of the block 210A, 210B, .. .

[0212] In addition, in FIG. 14, the number of blocks (number ofdivisions), being 5, is small, but if the optical penetrating rate ofthe incident lights is varied more finely by dividing into a largernumber of groups, the difference between the output from each area issmaller, and a fine adjustment of the shading (shading correction)becomes possible, allowing for the contrast steps of the image takenwith the solid-state image sensor 200 to be less visible.

[0213] In the following, a method for producing the solid-state imagesensor 200 of the above configuration will be explained using FIG. 15through FIG. 17.

[0214]FIG. 15 is a cross-sectional view showing a production process ofthe solid-state image sensor 200.

[0215] To produce the solid-state image sensor 200, first, at the top ofthe semiconductor substrate 210, a diffusion zone 232 constituting thelight-receiving part 202, or other diffusion zones constituting, forinstance, transistors, and signal lines are formed. Then, on the topside of these, the flattening layer 203, a color filter layer 204, amicro-lens stabilization layer 206 are formed (FIG. 15(a)). In addition,diffusion zones and signal lines not related to the present inventionare omitted from the Figure.

[0216] Then, a resin having propylene glycol monoethyl ether acetate(PGEEA), ethyl lactate (EL) and phenolic resin as the main components isused to spin-coat the top side of the semiconductor substrate 201, priorto patterning into the required shape with a publicly known lithographymethod, to form a rectangular micro-lens base 237 as shown in FIG. 5(b).

[0217] Then, a mask 250 is used, allowing the ultraviolet opticalpenetrating rate for ultraviolet lights to differ in a stepwise mannerfor the blocks 210A, 210B, . . . , 210E of the valid cell area 210, toexpose the micro-lens base 237 with ultraviolet light. This exposure toultraviolet light is performed to render the micro-lens base 237 formingthe micro-lens 207 transparent (back exposure), and the opticalpenetrating rate of the micro-lens base 237 is decreased by decreasingthe ultraviolet exposure dose (hereafter, simply called “back exposuredose”).

[0218] In addition, the optimum value for the back exposure dose dependson conditions (for instance the output of the light source) on the sideof the actual exposing apparatus used (omitted from the drawing).However, it is considered to be about 3 times the exposure dose used toexpose the resist used for the patterning of the micro-lens base 237(for instance, when using NSR150G4D (trademark) made by Nikon, it isabout 5 seconds).

[0219] Up to this stage of the process, in the central part 210A of thevalid cell area 210, a rectangular micro-lens base 237A having a lowoptical penetrating rate is formed, in the peripheral part 210E, arectangular micro-lens base 237AE having a high optical penetrating rate(more transparent) is formed, as shown in FIG. 15.

[0220] After the micro-lens bases 237A, . . . , 237E having differentoptical penetrating rates between the central part 210A and theperipheral part 210E have been formed, a heat treatment is performed(140° C. to 220° C.) on the semiconductor substrate 201, using a hotplate. With this heat treatment, the micro-lens bases 237A, . . . , 237Eare re-flow soldered to become hemispheric.

[0221] As a result, in the solid-state image sensor 200, a micro-lens207A having a low optical penetrating rate is formed in the central part210A, and a micro-lens 207E having a high optical penetrating rate isformed in the peripheral part 210E.

[0222] Here, the mask 250 used when exposing the micro-lens base 237 toultraviolet light will be explained.

[0223] As mentioned above, the optical penetrating rate of themicro-lens 207 of the valid cell area 210 is defined according to theblocks 210A, 210B, . . . (FIG. 14). Therefore, the mask 250 is alsodivided into a plurality of mask areas (5 in this case) 250A, 250B, . .. , 250E having different ultraviolet optical penetrating ratesaccording to these blocks 210A, 210B, . . . as shown in FIG. 16.

[0224] In each mask area 250A, 250B, . . . , 250E, the ultravioletoptical penetrating rate is adjusted by microscopic areas (a) through(e), where two types of microscopic squares are arranged to form amosaic, one type of microscopic square transmitting the ultravioletlight (white cutout in the drawing) and one type of microscopic squarenot transmitting the ultraviolet light (hatched part), shown in FIG. 17.This microscopic area (10 μm×10 μm size photodetecting cell) is dividedinto microscopic squares of 5×5.

[0225] In other words, the microscopic area (a) is formed in theabove-mentioned mask area 250A, the microscopic area (b) is formed inthe above-mentioned mask area 250B, the microscopic area (c) is formedin the above-mentioned mask area 250C, the microscopic area (d) isformed in the above-mentioned mask area 250D, and the microscopic area(e) is formed in the above-mentioned mask area 250E.

[0226] In this case, the ultraviolet optical penetrating rate is 0% inthe mask area 250A, the ultraviolet optical penetrating rate is 24% inthe mask area 250B, the ultraviolet optical penetrating rate is 52% inthe mask area 250C, the ultraviolet optical penetrating rate is 76% inthe mask area 250D, and the ultraviolet optical penetrating rate is 100%in the mask area 250E.

[0227] In addition, the larger the number of divisions into microscopicareas as shown in FIG. 17(a) to (e) , the smaller the irregularities dueto back exposure using the mask 250, and therefore, the more preferable.

[0228] In addition, to adjust the ultraviolet optical penetrating ratein each mask area 250A, 250B, . . . , 250E, it is possible to havedifferent area ratio between the two types of microscopic square.

[0229] In addition, it is acceptable to adjust the optical penetratingrate in each mask area 250A, 250B, . . . , 250E by pasting metal filmshaving different transparencies for each of the mask area 250A, 250B, .. . , 250E.

[0230] In the following, a single-lens reflex digital camera 300 loadedwith the solid-state image sensor 200 of the embodiment will beexplained.

[0231] As shown in FIG. 18, the single-lens reflex digital camera 300consists of a camera body 310, a view finder 320 and an exchangeablelens 330.

[0232] In this case, a photographic lens 331 and an iris 332 are builtinto the exchangeable lens 330 which is flexibly fastened to the camerabody 310.

[0233] In addition, a quick-turn mirror 311, a focus detector 312 and ashutter 313 are installed in the camera body 310. In addition, thesolid-state image sensor 200 is placed behind the shutter 313.

[0234] In addition, a finder mat 321, a pendaprism 322, an eye-piece323, a prism 324, an imaging lens 325 and a white balance sensor 326 areinstalled in the view finder 320.

[0235] In a single-lens reflex digital camera 300 configured asmentioned above, the light L30 from the subject is incident to thecamera body 310, through the exchangeable lens 330.

[0236] In this case, before release, the quick-turn mirror 311 is in theposition shown by the broken lines in the drawing, and therefore, aportion of the light L30 from the subject reflected by the quick-turnmirror 311 is directed into the view finder 320 and is imaged onto thefinder mat 321. A portion of the subject image taken at this point isdirected via the pendaprism 322 to the eye-piece 323, another portionbecomes incident to the white balance sensor 326 via the prism 324 andthe imaging lens 325. The white balance sensor 326 detects the colortemperature of the subject image. In addition, at this point, a portionof the light L30 from the subject is reflected by the auxiliary mirror311A affixed to the quick-turn mirror 311 and imaged onto the focusdetector 312.

[0237] After release, the quick-turn mirror 311 rotates clockwise in thedrawing (shown by solid lines in the Figure), and the light L30 from thesubject becomes incident to the shutter 313.

[0238] Therefore, when taking a picture, first, after the convergence ofthe focal point has been detected by the focus detector 312, the shutter313 opens. With the opening movement of the shutter 313, the light L30from the subject becomes incident to the solid-state image sensor 200and is imaged onto its light-receiving side.

[0239] The solid-state image sensor 200 which received the light L30from the subject, generates the electric signal corresponding to thelight L30 from the subject, and at the same time performs various imagesignal processing on the electric signal (see FIG. 37), such as awhite-balance correction based on signals from the white balance sensor326, and outputs the processed image signals (RGB data) to the buffermemory (omitted from the figure).

[0240] In the above image signal processing, the shading correction isperformed according to actual shading amounts. Therefore, in the digitalcamera loaded with the solid-state image sensor 200 of the invention,the influence of the shading is already removed from the signal chargeoutputted from the solid-state image sensor 200, and it is possible toomit the shading correction step in the image signal processing.

[0241] In addition, if enough shading correction could not be performedin the solid-state image sensor 200 due to, for instance, a variation inthe F number, it is possible to execute a shading correction at theimage signal processing stage. In this case, the difference or the colordifference being small, the system load due to shading correction issmall.

[0242] In the following, the results of measurements to assess how muchthe shading amount can be decreased by adjusting the optical penetratingrate of the micro-lens 207 will be described in detailed.

[0243] In this case, using a mask having the minimum ultraviolet opticalpenetrating rate (0%) and a mask having the maximum ultraviolet opticalpenetrating rate (100%), a back exposure of micro-lens was performed foreach (0% back exposure and 100% back exposure) and the extent of thechange for the optical penetrating rate of the micro-lens was measured.In addition, because it is not possible to directly measure the opticalpenetrating rate of a single micro-lens, the “G output voltage(equivalent to sensitivity etc. . . . ,)” obtained for each case havebeen compared.

[0244] To prevent any influence due to other factors from appearing inthe results of both measurements, the single-lens reflex digital cameraloaded with a solid-state image sensor with 0% back exposure and thesingle-lens reflex digital camera loaded with a solid-state image sensorwith 100% back exposure were placed against each other and positioned toalign the central axis of each camera lens, a picture was taken underthe same predetermined condition, and the “G output voltage” of theevent was measured. The camera lens used was a NIKKOR 50 mm F1.4S (trademark), and the subject was a uniformly bright picture without anypattern.

[0245] The “G output voltage” obtained in the above-mentioned conditionis shown in FIG. 19.

[0246] In the drawing, the broken line is the “G output voltage” of thesolid-state image sensor with 0% back exposure and the solid line is the“G output voltage” of the solid-state image sensor with 100% backexposure.

[0247] As is clear from the drawing, there is a difference of about 10%between the “G output voltage”. In addition, it can be established thatthe F number dependency of the difference in the “G output voltage” isextremely low.

[0248] By adjusting the ultraviolet optical penetrating rate of the mask250 between 0% and 100% as described above, the “G output voltage” ofthe solid-state image sensor can be varied by about 10%.

[0249] Therefore, when producing one solid-state image sensor 200, toperform the back exposure on the micro-lens 207, by using a mask 250 inwhich the ultraviolet optical penetrating rate differs in each of themask areas 250A, 250B, . . . , 250E, the optical penetrating rate of theblocks 210A, 210B, . . . , of the solid-state image sensor 200 can beconverted into “G output voltage” and freely adjusted within a range ofabout 10%.

[0250] In addition, the division of the valid cell area 210 into blocks210A, 210B, 210C, . . . is not limited to the pattern shown in FIG. 14,and, depending on the characteristics of the camera, or the user's idea,for example, as shown in FIG. 20, blocks 210A, 210B, 210C . . . can beformed by concentric circles from the center of the valid cell area 210,or as shown in FIG. 21, blocks 210A, 210B, 210C . . . can be formed asstripes in the vertical direction from the center of the valid cell area210. In this case, the longer direction of the valid cell area 210 isdivided into blocks 210A, 210B . . . since the convergingcharacteristics in the direction of the short axis (left-right directionof the FIG. 21) of the light-receiving part (photoelectric converter)202 of each photodetecting cell decreases when approaching theperipheral part (left and right edges, in the drawing) of the valid cellarea 210 and leading to a prominent shading, and by simply assigningblock 210A, block 210B, block 210C . . . as shown in FIG. 21, asufficient shading correction effect can be obtained.

[0251] In addition, without dividing the valid cell area 210 into blocks210A, block 210B, block 210C, . . . , an equivalent effect can beobtained by gradually changing the optical penetrating rate, for onephotodetecting cell (one light-receiving part 202) at a time, or for aplurality of photodetecting cells at a time.

[0252] In fact, in the embodiment, for each mask area 250A, 250 B, . . .of the mask 250, the ultraviolet optical penetrating rate isadvantageously set to 0%, 24%, 52%, 76% and 100%. The “G output voltage”actually obtained in this case, when the ultraviolet optical penetratingrate of the mask 250 falls into the 100% to 52% range, showed anincrease following the order 100%>76%>52%. However, when the ultravioletoptical penetrating rates were 52%, 24%, 0%, no noticeable differencecould be identified. As shown previously, there is an appropriate rangefor the ultraviolet exposure rate of the mask 250 for displaying aneffect on the “G output voltage (corresponding to the opticalpenetrating rate)”. Therefore, by setting the ultraviolet opticalpenetrating rate within the aforementioned appropriate range, a desiredoptical penetrating rate can be easily realized for a valid cell area ata desired position of the solid-state image sensor.

Sixth Embodiment

[0253] In the following, the sixth embodiment according to the inventionwill be explained using FIG. 22.

[0254] The sixth embodiment is the solid-state image sensor 200 whereinthe micro-lens 207 is formed by a so-called “etch back method”.

[0255] Also in the sixth embodiment, first, at the top of asemiconductor substrate 201 the diffusion zone 232 constituting thelight-receiving part 202 is formed, on top of these, the flatteninglayer 203, the color filter layer 204, the micro-lens stabilizationlayer 206 are formed (FIG. 22(a)) Then a uniform micro-lens layer 261 isformed by spin-coating (FIG. 22(b)).

[0256] A photoresist layer 262 then coats the top side of the micro-lenslayer 261 formed, to transfer the shape of the micro-lens 207, prior topatterning the photoresist layer with the desired shape by thephotolithography technique (FIG. 22(c) ) A heat treatment is performedon the photoresist layer 262 patterned with the desired shape, andre-flow soldered to form a hemispheric photoresist layer 263 (FIG. 22(d)).

[0257] Next, dry etching is performed on the hemispheric resist layer263 which is then etched back to transfer the hemispheres from theresist layer 263 onto the micro-lens layer 261. The result is theformation of a hemispheric micro-lens 267 whose transparency is notsufficient (FIG. 22(e) ).

[0258] Finally, “back exposure” is performed on the hemisphericmicro-lens layer 267 to render it transparent. The conditions for the“back exposure” are the same as in the fifth embodiment, and the detailsare omitted here (FIG. 22(f) ).

[0259] By performing the above “back exposure”, a micro-lens 267 (267A,267E) is obtained, wherein the optical penetrating rate is differentbetween the central part 210A and the peripheral part 210E (FIG. 22(g)).

[0260] In addition, in the sixth embodiment, the “back exposure” isperformed onto a hemispheric micro-lens 267 formed by the etch backmethod. However, this does not constitute a limitation, and forinstance, immediately after coating the micro-lens layer 261, “backexposure” can be performed on the micro-lens layer 261, and the opticalpenetrating rate (transparency) of the micro-lens 267 changed, at thisstage. Then, in this case, a hemispheric micro-lens 267 is formed by theabove-mentioned etchback method.

Seventh Embodiment

[0261] In the following, the seventh embodiment in relation to themethod of production of the solid-state image sensor 200 will beexplained using FIG. 23.

[0262] In the above-mentioned fifth and sixth embodiments, to obtain adifferent optical penetrating rate for the micro-lens 207, theirradiation amount during “back exposure” of the micro-lens 207 or themicro-lens layer 261 has been differentiated, in the seventh embodimentthe temperature distribution is differentiated when performing the heattreatment on the hemispheric micro-lens 207 to obtain a micro-lens 207in which the optical penetrating rate follows the temperaturedistribution.

[0263] The embodiment exploits the characteristics of the micro-lenslayer 261 having propylene glycol monoethyl ether acetate (PGEEA), ethyllactate (EL) and phenolic resin as the main components, whose opticalpenetrating rate becomes lower when heated with high temperatures.

[0264] In the following, the heat treatment of hemispheric micro-lens207 formed on the micro-lens stabilization layer 206 will be explained.

[0265] In addition, except for the fact that “back exposure” is notperformed, the other production processes are identical to the fifth andsixth embodiments.

[0266] To heat the micro-lens 207 installed on the valid cell area 210of the solid-state image sensor 200, with a different temperature foreach of the block 210A, block 210B, etc. . . . , a hot plate 280 shownin FIG. 23(a) is used.

[0267] Protruding arc-shaped parts 281, 281, . . . are formed on thesurface of the hot plate 280. On the surface of the hot plate 280, asemiconductor wafer W, in which a plurality of solid-state image sensorare formed, is placed face-down.

[0268] In this case, in the central part 210A of each solid-state imagesensor 200, the micro-lens 207 is separated by a slight gap d41 andfaces the apex parts 282, 282, . . . of each protruding part 281, 281, .. . of the hot plate 280, (FIG. 23(b)). At this point, the central part210A is heated approximately at the temperature set for the hot plate280 (for example 220° C.).

[0269] On the other hand, in the peripheral part 210E of the solid-stateimage sensor 200, the micro-lens 207 is separated by a predetermineddistance d42 (for instance 1 mm to 5 mm) and faces the bottom part 283,283, . . . , of the hot plate 280 (FIG.23(b)). The peripheral part 210Eis heated at a temperature lower than the temperature set for the hotplate 280 (220° C.) due to the predetermined distance d42.

[0270] As described above, by setting the temperature of the hot plate280 and the predetermined distance d42 to desired values, the opticalpenetrating rate of the micro-lens 207 (207A) of the central part 210Aand the optical penetrating rate of the micro-lens 207 (207E) of theperipheral part 210E of the solid-state image sensor 200 can be adjustedto different values.

[0271] In this case, an alignment mark 209A as shown in FIG.23(a) isrequired to superimpose the hot plate 280 and the semiconductor wafer W,and when the hot plate 280 and the semiconductor wafer w aresuperimposed, the difference in the alignment is at maximum 0.5 mm, andeven if the superposition is offset by this maximum value, the influenceon the decrease of shading amount is not important. Particularly, for asolid-state image sensor 200 having a large valid cell area 210, even ifthe center of the photodetecting cell in the area where the opticalpenetrating rate is lowered (central part 210 A) is offset from thecenter of the valid cell area 210 of the solid-state image sensor 200,the influence on the whole image is small.

Eighth Embodiment

[0272] In the following, the eighth embodiment according to theinvention will be explained using FIG. 24 to FIG. 26.

[0273] A solid-state image sensor 400 of the eighth embodiment, hasoptical penetrating amounts of incident light varied in a central part410A and a peripheral part 410E obtained by differentiating the opticalpenetrating rate of a flattening layer 403 underneath a micro-lens 407.

[0274] In other words, the method for producing the solid-state imagesensor 400 of the eighth embodiment exploits the characteristics of theflattening layer 403 having propylene glycol monomethyl ether acetate(PGMEA) and propylene glycol monoethyl ether acetate (PGEEA) as the maincomponents, whose optical penetrating rate becomes lower when heatedwith high temperatures.

[0275] The solid-state image sensor 400 of the eighth embodimentconsists of a semiconductor substrate 401, a light-receiving part 402,the flattening layer 403, a color filter layer 404, a micro-lensstabilization layer 406, the micro-lens 407. In addition, all layers butthe flattening layer 403 are identical to the fifth embodiment and thedetailed explanation thereof will be omitted.

[0276] In this case, to vary the optical penetrating rate of theflattening layer 403, a heat treatment is performed on the flatteninglayer 403 to differentiate the temperature distribution, before themicro-lens 407 is formed on the surface the flattening layer 403.

[0277] To differentiate the temperature for heating the flattening layer403, between the central part 410A and the peripheral part 410E of thesolid-state image sensor 400, a hot plate 280 identical to the seventhembodiment is used (FIG. 25(a)).

[0278] When heating, as shown in FIG. 25(a) and (b) , a semiconductorwafer W, is placed face-down and in the central part 410A of eachsolid-state image sensor 400, the flattening layer 403 is separated by aslight gap d51 and faces the apex parts 282, 282, . . . of eachprotruding part 281, 281, . . . of the hot plate 280, (FIG. 25(b)). Atthis point, the central part 410A is heated approximately at thetemperature set for the hot plate 180 (for example 240° C.).

[0279] In the peripheral part 410E of the solid-state image sensor 400,the flattening layer 403 is separated by a predetermined distance d42(for instance 1 mm to 5 mm) and faces the bottom part 183, 183, . . . ,of the hot plate 180 (FIG. 25(b)). The peripheral part 410E is heated ata temperature lower than the temperature set for the hot plate 180 (240°C.) due to the predetermined distance d42.

[0280] Therefore, by setting the temperature of the hot plate 180 andthe predetermined distance d42 to desired values, the opticalpenetrating rate of the flattening layer 403 of the central part 410Aand the optical penetrating rate of the flattening layer 403 of theperipheral part 410E of the solid-state image sensor 400 can be adjustedto different values.

[0281] The broken line in FIG. 26 show the results of measurementsperformed on a solid-state image sensor wherein the shading amount isdecreased by changing the optical penetrating rate of the flatteninglayer 403 within the valid cell area 410.

[0282] The above-mentioned measurement results are calculated values of“effective aperture rates” when using a solid-state image sensor 400wherein the valid cell area 410 was 25.1 mm in the horizontal directionand 16.9 mm in the vertical direction, and the optical penetrating rateof the peripheral part of the flattening layer 403 of the solid-stateimage sensor 400 was 100% and the optical penetrating rate of thecentral part of the flattening layer 403 of the solid-state image sensor400 was 70%.

[0283] In this case, the “effective aperture rate” is (amount ofincident light at the level of the photovoltaics)/(total amount ofincident light at the level of a photodetecting cell unit). This“effective aperture rate” corresponds to the “G output voltage”

[0284] In addition, in FIG. 26, Δ is the actually measured value ofeffective aperture rate for the central part (correspond to thesensitivity, the G output voltage) and □ is the calculated value of theeffective aperture rate for the peripheral part.

[0285] When the results of the measurements of FIG. 26 are compared tothe case of a solid-state image sensor of the prior art wherein all thestructures but the flattening layer are the same (for examplesolid-state image sensor 20 of FIG. 36), the ratio between the“effective aperture rate” of the central part 410A and the “effectiveaperture rate” of the peripheral part 410E is greater for lower Fnumbers. This indicates that the shading amount can be considerablydecreased.

[0286] The above-mentioned ratio of the “effective aperture rate” couldbe improved to about 73%, when comparing the cases where the flatteninglayer 403 of the eighth embodiment is used and when it is not used (inthe measurements of FIG. 36 the ratio of the “effective aperture rate”between the peripheral part and the central part is about 45% at F1.4).

Ninth Embodiment

[0287] In the following, the ninth embodiment according to the inventionwill be explained using FIG. 27 to FIG. 30.

[0288] In the solid-state image sensor 500 of the ninth embodiment, theoptical penetrating rate to incident light at the level of the centralpart and the peripheral part, is controlled by an optical penetratingrate controlling layer 600 attached as one piece on the light-receivingside to the solid-state image sensor 500. In the embodiment, an allsolid-type electro-chromic element (hereafter EC layer) is used as theoptical penetrating rate controlling layer 600.

[0289] The solid-state image sensor 500 of the ninth embodiment, ishoused in the packaging base 502 and attached on the print-base 501 ofthe digital camera, as shown in FIG. 27.

[0290] The optical penetrating rate controlling layer 600 attached tothe upper part of the solid-state image sensor 500, is divided into aplurality of blocks 610A, 610B, . . . , and can control the opticalpenetrating rate for each of the blocks 610A, block 610B . . . , asshown in FIG. 27(b).

[0291] In addition, a plurality of ITO electrodes 611 are installed onthe optical penetrating rate controlling layer 600 to handle each of theblock 610A, block 610B. . . The aforementioned ITO electrodes 611A,611B, . . . are electrically connected via the wiring part 632 to theconnecting part 633 formed at one end of the optical penetrating ratecontrolling layer 600.

[0292] Then, a variable voltage controller 620 is electrically connectedvia the wires 631, 631, . . . to the connecting part 632,

[0293] The desired voltage is supplied from the variable voltagecontroller to each ITO electrode 611A, 611B, individually.

[0294] Here, the structure of the optical penetrating rate controllinglayer (EC layer) 600 will be explained.

[0295] The optical penetrating rate controlling layer (EC layer) 600consists of an anti-reflecting layer 601A, a cover glass 602, atransparent adhesive layer 603, a lower ITO layer 604A, a tungstatelayer 605, a tantalate layer 606, an irradiate layer 607, a furtherupper ITO layer 604B, glass substrate 604B and an anti-reflecting layer601B.

[0296] In this case, the irradiate layer 607 is sandwiched between thelower ITO layer 604A and the upper ITO layer 604B. In addition, thelower ITO layer 604A and upper ITO layer 604B form the ITO electrodes611, 612, . . . .

[0297] In an optical penetrating rate controlling layer (EC layer) 600having the previously-described configuration, the difference inelectric potential between the ITO layer 604A and the ITO layer 604B iscontrolled and makes it possible to adjust the optical penetrating rateof the irradiate layer 607.

[0298] In addition, to control the optical penetrating rate of theirradiate layer using the optical penetrating rate controlling layer (EClayer) 600, it is sufficient to change the difference in electricpotential between the ITO layer 604A and the ITO layer 604B within aspecified range (−1.0 to 1.3 V, for example). This makes it possible tocontrol gradually and reversibly the optical penetrating rate for theincident light (wavelength 633 nm, for example) from about 70% to 17%(studies by Ishikawa et al., Nippon Shashin Gakkai Shi, Vol. 60, No 5,1997/9, pp. 303-306).

[0299] Therefore, in the embodiment, for example, by setting thedifference in electric potential of the ITO electrodes 611, 612, . . .in the block 610A, 610B, . . . to +1.3V for block 610A, to +0.8V forblock 610B, to +0.6V for block 610C, to +0.4V for block 610D, to 0V forblock 610E and to −1.0V for block 610F, optical penetrating rate can beset to about 17%, 28%, 40%, 50%, 65% and 70%, from the central part tothe peripheral part of the solid-state image sensor 500. In this case, acorrection of 4.1 times is possible for the optical penetrating amountbetween the central part and the peripheral part of the solid-stateimage sensor 500.

[0300] Therefore, even for a solid-state image sensor having anextremely large valid cell area (for instance, with 35mm in thehorizontal direction and 24 mm in the vertical direction), the shadingamount can be decreased as an entire solid-state image sensor 500 bycontrolling the optical penetrating rate of the peripheral part wherethe decrease in brightness due to shading is significant, and thecentral part where the influence of shading is not important.

[0301] In addition, the ITO electrodes 611A, 611B, . . . arecharacterized by a blurred contour of the limit between an area wherethe electrode is on and an area where the electrode is off, therefore,in an optical penetrating rate controlling layer (EC layer) 600 usingITO electrodes 611A, 611B, . . . , the limits between each of the block610A, 610B, . . . are not displayed in the image after shadingcorrection.

[0302] In the following, the outline of the control of the opticalpenetrating rate of the optical penetrating rate controlling layer (EClayer) 600 by the variable voltage controller 620 will be explained.

[0303] To control the optical penetrating rate of the block 610A, 610B,. . . of the optical penetrating rate controlling layer (EC layer) 600,light sensors 561, . . . are placed in the surroundings of thesolid-state image sensor 500, as shown in FIG. 29.

[0304] Then, when taking a picture with the digital camera 300 (FIG. 18)fitted with the solid-state image sensor 500, by determining the voltageprovided to the ITO electrodes 611A, 611B, . . . , based on the signalsof said sensors 561, the amount of shading can be decreased according toan actual environment for taking photographic pictures (without beinginfluenced by the F number).

[0305]FIG. 30 shows a variation example of the optical penetrating ratecontrolling layer (EC layer).

[0306] The optical penetrating rate controlling layer (EC layer) 700 inrelation to the variation example differs from the optical penetratingrate controlling layer (EC layer) 600 in the layout of blocks 710A,710B, . . . and ITO electrodes 711A, 711 B, . . . In other words, in theoptical penetrating rate controlling layer (EC layer) 700, the variablevoltage controller 620 and the ITO electrodes 711A, 711B, . . . aredirectly connected through wires. Therefore, a wiring part directing theelectrodes 711A, 711B, . . . to the periphery of the optical penetratingrate controlling layer (EC layer) 700 is no longer necessary. Thisallows for a larger optical penetrating rate control surface to bemaintained.

Tenth Embodiment

[0307] In the following, the tenth embodiment according to the inventionwill be explained using FIG. 31.

[0308] The tenth embodiment is the same as the ninth embodiment but anoptical penetrating rate controlling layer (EC layer) 800 is usedreplacing the optical penetrating rate controlling layer (EC layer) 600and 700 used to adjust the optical penetrating amount of solid-stateimage sensor 500.

[0309] The above-mentioned optical penetrating rate controlling layer(EC layer) 800 can control the optical penetrating amount of theincident lights at a central part 810A and a peripheral part 810B, atthe level of each of the photodetecting cells.

[0310] In other words, ITO electrodes 811, 811 of the solid-state imagesensor 500 are placed in the X direction (horizontal direction) and theY direction (vertical direction) to form a matrix. An X electrode drivecircuit 821 and a Y electrode drive circuit 822 are connected to theseITO electrodes 811, 811. . . .

[0311] The control circuit 823 determines the voltage (difference inelectric potential) that should be supplied for each of the ITOelectrodes 811, 811, . . . , and supplies the desired voltage to each ofthe desired ITO electrode 811, 811, . . . through the X electrode drivecircuit 821 and a Y electrode drive circuit 822.

[0312] As a result, in the optical penetrating rate controlling layer(EC layer) 800, the optical penetrating amount of the incident lightscan be controlled for each ITO electrode 811, 811, . . . , in otherwords, for each photodetecting cell In addition the voltage value foreach photodetecting cell (corresponding to the optical penetrating rate)can be determined based on the signal from the above-mentioned sensor561, . . . (FIG. 26).

[0313] Using the optical penetrating rate controlling layer (EC layer)800, the shading amount can be decreased at the level of each of thephotodetecting cell of the solid-state image sensor, according to theenvironment of a digital camera taking a picture. Therefore, when thecamera lens of the digital camera is exchanged for an exchangeable lens,or in cases where the focus is adjusted and the effective F number ischanged, in each of such cases, there can be an optimal decrease ofshading adapted to the conditions for taking pictures.

[0314] In addition, in the optical penetrating rate controlling layer(EC layer) of the ninth and tenth embodiment, a static voltage supplyhas been given as an example. However, the advantage of using theoptical penetrating rate the controlling layer (EC layer) 600, 700 and800 lies in that they allow for the electric source to vary, providing arapid control of the optical penetrating rate to obtain a desired value.Using this function, when taking pictures with the digital camera, thebrightness of the subject before the shutter motion can be read-inbeforehand, and using the read-in brightness distribution, the amount ofshading correction can be determined. According to the amount of shadingcorrection thus obtained, the voltage to be supplied is determined, andthe shutter is opened for the picture to be taken (in situ shadingcorrection).

[0315] In addition, the optical penetrating rate of the opticalpenetrating rate controlling layer (EC layer) 600, 700 and 800 arecontrollable with good responses and according to the results obtainedin the studies on the speed of the EC layers response, from thepreviously-indicated “studies by Ishikawa et al., Nippon Shashin GakkaiShi, Vol. 60, No 5, 1997/9, pp. 303-306”, it is certain that the changeof optical penetrating rate will be completed in about 100-200 ms.Therefore, the optical penetrating rate controlling layer (EC layer) canbe applied to the shading correction when taking pictures with an actualdigital camera 300.

[0316] In addition, the above-mentioned ninth and tenth embodiments, areusing the brightness information from the light sensor 561 placed in thesurroundings of the valid cell area 510 of the solid-state image sensor500 for shading correction. However, to obtain an optimal amount ofshading correction, it is possible to obtain the brightness distributionin the valid cell area 510 beforehand. Among means to obtain beforehandthe brightness distribution in the valid cell area 510, a possibility isto calculate the brightness information based on image data alreadyobtained by the solid-state image sensor 500, or, based on dataextracted from an image data.

[0317] In addition, in the ninth and tenth embodiments, the exampleswere given with the optical penetrating rate controlling layers (EClayer) 600, 700 and 800 placed on the light receiving side of thesolid-state image sensor 500, however, the position for placing theoptical penetrating rate controlling layer s (EC layer) 600, 700 and 800may not necessarily be as specified. For instance, a sealing glass maybe installed on the package 502 in which the solid-state image sensor issealed, and the optical penetrating rate controlling layers may beplaced above that. In addition, it is also possible to bring thesolid-state image sensor 500 and the optical penetrating ratecontrolling layer (EC layer) 600, 700, and 800, into contact, withoutleaving an interval in between.

[0318] In addition, the optical penetrating rate controlling layer (EClayer) 600, 700 and 800, may be placed in the space from theexchangeable lens 320 of the single-lens reflex digital camera 300 up tothe solid-state image sensor 500.

[0319] In addition, in the above-mentioned ninth and tenth embodiments,explanations were given taking the example EC layers with integratedstructures as the optical penetrating rate controlling layers (EC layer)600, 700 and 800, however, other layers capable of controlling theoptical penetrating rate (for example, a liquid-crystal layer) may alsobe used.

[0320] In addition, in the above-mentioned fifth through tenthembodiment, explanations were given with examples using a charge-coupleddevice-type image sensor as the solid-state image sensor, however, it isevident that the invention is applicable to other solid-state imagesensors in which shading may occur (amplification image sensors, CMOSimage sensors, etc . . .

[0321] In addition, it is evident that instead of the above-mentionedcharge-coupled device-type image sensor (CCD), the invention isapplicable to solid-state image sensors disclosed by the inventors inthe patent No Hei. 11-87680, in other words, an amplification-type imagesensor wherein implant photodiodes serving as the light-receiving part,and J-FET (junction-type FET) serving as the amplifier are placed ineach photodetecting cell.

[0322] In addition, in each embodiment from the first through thefourth, it is evident that a configuration in which the aperture surfaceof the light blocking layer of the photodetecting cell in the peripheralpart of the valid cell area is increased to be larger than the aperturesurface of the light blocking layer of the photodetecting cell in thecentral part of the valid cell area to further limit the shading amount,is possible and is included in the scope of the invention.

[0323] The invention is not limited to the above embodiments and variousmodifications may be made without departing from the spirit and scope ofthe invention. Any improvement may be made in part or all of thecomponents.

What is claimed is:
 1. A solid-state image sensor comprising: a validcell area wherein a plurality of valid cells are placed, said validcells each having a light-receiving part and a color filter placed in anon-chip fashion to correspond to said light-receiving part, andoutputting a charge signal, wherein: said color filter placed in theperipheral part of said valid cell area has the center offset in thedirection to the center of said valid cell area with respect to thecenter of said light-receiving part; and “offset amounts” between thecenters of a plurality of said color filters and the centers of aplurality of said light-receiving parts become gradually or continuouslylarger, the further it is from the central part and the closer it is tothe peripheral part of the valid cell area.
 2. The solid-state imagesensor according to claim 1 , wherein: said valid cells are grouped intoa plurality of concentric blocks; and said “offset amounts” between thecenters of said color filters and the centers of said light-receivingparts become larger, the further it is from the central part and thecloser it is to the peripheral part of said valid cell area, in whichthe photodetecting cells within the same block have the same “offsetamount”.
 3. The solid-state image sensor according to claim 1 , wherein:said valid cell has a light blocking layer having an aperturecorresponding to said light-receiving part; said aperture of said validcell reserved in the peripheral part of said valid cell area has thecenter offset in the direction to the center of said valid cell areawith respect to the center of said light-receiving part; and the “offsetamount” between the center of said aperture and the center of saidlight-receiving part become gradually or continuously larger, thefurther it is from the central part and the closer it is to theperipheral part of said valid cell area.
 4. The solid-state image sensoraccording to claim 1 , wherein said valid cell has a micro-lens placedin an on-chip fashion to correspond to said light-receiving part.
 5. Thesolid-state image sensor according to claim 4 , wherein: said validcells are grouped into a plurality of concentric blocks; and said“offset amounts” between the centers of said apertures and the centersof said light-receiving parts of said valid cells become larger, thefurther it is from the central part and the closer it is to theperipheral part of said valid cell area, in which said “offset amount”is the same within the same block.
 6. A solid-state image sensorcomprising: a valid cell area wherein a plurality of valid cells areplaced, said valid cells having a light-receiving part and a colorfilter placed in an on-chip fashion to correspond to saidlight-receiving part, and outputting a charge signal, wherein: saidcolor filter placed in the peripheral part of said valid cell area hasthe center offset in the direction to the center of the valid cell areawith respect to the center of said light-receiving part; and saidlight-receiving parts and said color filters are respectively placed intheir predetermined pitches, the pitch said light-receiving parts areplaced in being greater than the pitch said color filters are placed in.7. The solid-state image sensor according to claim 6 , wherein: saidvalid cell has a light blocking layer having an aperture correspondingto said light-receiving part; said aperture of said valid cell reservedat the peripheral part of said valid cell area has the center offset inthe direction to the center of said valid cell area with respect to thecenter of said light-receiving part; and said apertures are reserved ata predetermined pitch which is smaller than the pitch saidlight-receiving parts are placed in and greater than the pitch saidcolor filters are placed in.
 8. The solid-state image sensor accordingto claim 6 , wherein said valid cells have micro-lenses placed in anon-chip fashion in a predetermined pitch, to correspond with saidlight-receiving part, and the pitch said color filters are placed in isgreater than the pitch said micro-lenses are placed in.
 9. Thesolid-state image sensor according to claim 8 , wherein when valid cellhaving the center of said color filter offset with respect to the centerof said light-receiving part have: an offset between the center of saidlight-receiving part and the center of said color filter placed in saidvalid cell, of SOCF; an offset between the center of saidlight-receiving part and the center of said micro-lens, of Sm; totalthickness of layers between said light-receiving part and the layer onwhich said micro-lens is mounted, of d1; and thickness of layer(s)between said light-receiving part and said color filter, of d2, theconfiguration thereof satisfies 0.7×(d1/d2)≦Sm/SOCF≦1.3×(d1/d2).
 10. Asolid-state image sensor comprising: a valid cell area wherein aplurality of valid cells are placed, said valid cells having alight-receiving part and a blocking layer having an aperture reserved tocorrespond to said light-receiving part, and outputting a charge signal,wherein said aperture of said valid cell reserved at the peripheral partof said valid cell area has the center offset to the direction of thecenter of said valid cell area with respect to the center of saidlight-receiving part, and “offset amounts” between the centers of saidapertures and the centers of said light-receiving parts becomesgradually or continuously larger, the further it is from the centralpart and the closer it is to the peripheral part of said valid cellarea.
 11. The solid-state image sensor according to claim 10 , wherein:said valid cells are grouped into a plurality of concentric blocks; andsaid “offset amounts” between the centers of said apertures and thecenters of said light-receiving parts of said valid cells become larger,the further it is from the central part and the closer it is to theperipheral part of said valid cell area, in which said “offset amount”is the same within the same block.
 12. The solid-state image sensoraccording to claim 10 , wherein said valid cell has a micro-lens placedin an on-chip fashion to correspond to said light-receiving part. 13.The solid-state image sensor according to claim 12 , wherein when validcell having the center of said aperture offset with respect to thecenter of said light-receiving part have: said offset between the centerof said light-receiving part placed in said valid cell and the center ofsaid aperture reserved at said valid cell, of SOPN; said offset betweenthe center of said light-receiving part and the center of saidmicro-lens, of Sm; total thickness of layers between saidlight-receiving part and the layer on which said micro-lens is mounted,of d1; and thickness of layer(s) between said light-receiving part andsaid aperture, of d3, the configuration thereof satisfies0.7×(d1/d3)≦Sm/SOPN≦1.3×(d1/d3).
 14. A solid-state image sensorcomprising: a valid cell area wherein a plurality of valid cells areplaced, said valid cells having a light-receiving part placed and anaperture reserved to correspond to said light-receiving part, andoutputting a charge signal, wherein: said aperture reserved at theperipheral part of said valid cell area has the center offset in thedirection to the center with respect to the center of saidlight-receiving part; and said light-receiving parts are respectivelyplaced and said apertures are respectively reserved in theirpredetermined pitches, the pitch said light-receiving parts are placedin being greater than the pitch said aperture is reserved at.
 15. Thesolid-state image sensor according to claim 14 , wherein said validcells have micro-lenses placed in an on-chip fashion in a predeterminedpitch, to correspond with said light-receiving part, and the pitch saidapertures are reserved at is greater than the pitch said micro-lensesare placed in.
 16. The solid-state image sensor according to claim 15 ,wherein when the valid cell having the center of said aperture offsetwith respect to the center of said light-receiving part have: saidoffset between the center of said light-receiving part placed in saidvalid cell and the center of said aperture reserved at said valid cell,of SOPN; said offset between the center of said light-receiving part andthe center of said micro-lens, of Sm; total thickness of layers betweensaid light-receiving part and the layer on which said micro-lens ismounted, of d1; and thickness of layer(s) between said light-receivingpart and said aperture, of d3, the configuration thereof satisfies0.7×(d1/d3)≦Sm/SOPN≦1.3×(d1/d3)
 17. A digital camera comprising anoptical system including an iris, and a solid-state image sensor,wherein: said solid-state image sensor comprises a valid cell areawherein a plurality of valid cells are placed, said valid cell having alight-receiving part and a color filter placed in an on-chip fashion tocorrespond to said light-receiving part, and outputting a charge signal,in which said valid cell further has a light blocking layer having anaperture corresponding to said light-receiving part; said color filterplaced in the peripheral part of said valid cell area has the centeroffset in the direction to the center with respect to the center of saidlight-receiving part; said light-receiving part and said color filterare placed in their respective predetermined pitches, the pitch saidlight-receiving parts are placed in being greater than the pitch saidaperture is reserved at; said aperture of said valid cell reserved atthe peripheral part of said valid cell area has the center offset in thedirection to the center of said valid cell area with respect to thecenter of said light-receiving part; said apertures are reserved at apredetermined pitch which is smaller than the pitch said light-receivingparts are placed in and greater than the pitch of said color filters areplaced in; when the offset between the center of said light-receivingpart and the center of said micro-lens is Sm, the offset between thecenter of said light-receiving part and the center of said color filterplaced in said valid cell is SOCF, the offset between the center of saidlight-receiving part placed in said valid cell and the center of saidaperture reserved at said valid cell is SOPN, total thickness of layersbetween said light-receiving part and the layer on which said micro-lensis fitted is d1, thickness of layer(s) between said light-receiving partand said color filter is d2, and thickness of layer(s) between saidlight-receiving part and said aperture is d3, each said thickness oflayer(s) fulfills the relation SOPN<SOCF<Sm; and when the refractiveindex of the layers placed underneath said micro-lens is n, said opticalsystem has an eye-relief of 1 , and the height of the image is p in saidphotodetecting cell of aforementioned solid-state image sensor, at leastone of 0.7×d1×tan θ≦Sm≦1.3×d1×tan θ,0.7×d2×tan θSOCF≦1.3×d2×tan θ, and0.7×d3×tan θ≦SOPN≦1.3×d3×tan θ is satisfied, and sin θ=p/[n×(p²+1²)^(½)] is satisfied.
 18. A solid-state image sensor comprising: aplurality of photovoltaics arrayed on the main side of a semiconductorsubstrate, to form a valid cell area made of a plurality of valid cells;and penetration adjusting means, for adjusting the optical penetratingamount of said incident lights according to the position of saidphotovoltaics in said valid cell area, placed on the incident side ofthe photovoltaics.
 19. The solid-state image sensor according to claim18 , wherein said penetration adjusting means is a layer made of organicmaterials formed in the top part of the photovoltaics, and formed sothat the optical penetrating rate is different according to the positionin the valid cell area.
 20. The solid-state image sensor according toclaim 19 , further comprising micro-lenses formed on the incident sideof said photovoltaics, configured to have different optical penetratingrates which change from the peripheral part to the central part of saidvalid cell, due to said layer made of organic material.
 21. Thesolid-state image sensor according to claim 19 , further comprisingmicro-lenses placed above said photovoltaics, and wherein said layermade of organic materials is a flattening layer between saidphotovoltaics and said micro-lenses.
 22. The solid-state image sensoraccording to claim 18 , wherein: said valid cell area is divided into aplurality of blocks such as concentric rectangles, concentric circles orstrips; and said penetration adjusting means adjusts the opticalpenetrating amount of light reaching the same block to be uniform, andto have a greater optical penetrating amount, the closer to theoutermost part of said valid cell area the block is.
 23. A method forproducing a layer, made of organic material, formed on the incident sideof a plurality of photovoltaics in a solid-state image sensor arrayed onthe main side of a semiconductor substrate, said layer having differentoptical penetrating rates according to the position of saidphotovoltaics within a valid cell area made of a plurality of validcells, comprising the steps of: forming a layer is whose opticalpenetrating rate changes according to the ultraviolet irradiationamount; and selectively irradiating to said layer an amount ofultraviolet ray which corresponds to the position in said valid cellarea.
 24. A method for producing a layer, made of organic material,formed on the incident side of a plurality of photovoltaics in asolid-state image sensor arrayed on the main side of a semiconductorsubstrate, said layer having different optical penetrating ratesaccording to the position of said photovoltaics within a valid cell areamade of a plurality of valid cells, comprising the steps of: forming alayer is whose optical penetrating rate changes according to thetemperature of heat treatment; and heat-treating said layer at atemperature which corresponds to the position in said valid cell area.25. The solid-state image sensor according to claim 18 , wherein: saidpenetration adjusting means is positioned on the incident side of saidvalid cell area, and is optical penetrating rate controlling meanscapable of controlling the optical penetrating rate.
 26. The solid-stateimage sensor according to claim 25 , wherein said optical penetratingrate controlling means controls the optical penetrating rate based on asignal from a brightness sensor mounted around said valid cell area. 27.The solid-state image sensor according to claim 25 , wherein saidoptical penetrating rate controlling means is a layer usingelectro-chromic elements.
 28. The solid-state image sensor according toclaim 18 , wherein said penetration adjusting means respectively adjuststhe optical penetrating amount for each photodetecting cell.
 29. Adigital camera comprising a solid-state image sensor, having: aplurality of photovoltaics arrayed on the main side of a semiconductorsubstrate, to form a valid cell area made of a plurality of valid cells;and penetration adjusting means, for adjusting the optical penetratingamount of the said incident light according to the position of saidphotovoltaics in said valid cell area, placed on the incident side ofsaid photovoltaics.
 30. A digital camera comprising: a camera lens; anda solid-state image sensor, having: a plurality of photovoltaics arrayedon the main side of a semiconductor substrate, to form a valid cell areamade of a plurality of valid cells; and penetration adjusting means, foradjusting the optical penetrating amount of the said incident lightaccording to the position of said photovoltaics in said valid cell area,placed on the incident side of said photovoltaics, and placed betweensaid solid-state image sensor and said camera lens.